Course: Physics

I. Grade Level/Unit Number: Physics Unit 5

II: Unit Title: Work and Energy

III. Unit Length: 10 days (block schedule) or 18 days (traditional schedule)

IV. Major Learning Outcomes:

This unit is focused on the concepts of work and energy. Students will learn about the relationships between force, displacement, kinetic energy, and potential energy. Specifically students will be able to:

Application of Graphical and Mathematical Tools Work:

Identify work as a transfer of energy Recognize work as the area under a force vs. distance graph

Conservation of energy: Describe energy transfer and storage in a variety of physical system Solve problems using conservation of energy Design and conduct experiments exploring conservation of energy

Power: Define power as the rate at which work is done Solve problems involving work and power

V. Content Objectives Included (with RBT Tags):

COMPETENCY GOAL 1: The learner will develop abilities necessary to do and understand scientific inquiry.

1.01 Identify questions and problems that can be answered through scientific investigations.

(RBT B2, B3, C2, C3)

This goal and these objectives are an integral part of each of the other goals. In order to measure and investigate scientific phenomena, students must be given the opportunity to design and conduct their own investigations in a safe laboratory. The students should use questions and models to formulate the relationship identified in their investigations and then report and share those finding with othersStudents will be able to:

Develop questions for investigation from a given topic or

Physics- Unit 5 DRAFT 1

problem.

1.02 Design and conduct scientific investigations to answer questions about the physical world.• Create testable hypotheses.• Identify variables.• Use a control or comparison group when appropriate.• Select and use appropriate measurement tools.• Collect and record data.• Organize data into charts and graphs.• Analyze and interpret data.• Communicate findings.

(RBT C2, C3, C4, C5, C6)

Distinguish and appropriately graph dependent and independent variables.

Discuss the best method of graphing/presenting particular data.

Use technology resources such as graphing calculators and computers to analyze data.

Report and share investigation results with others.

1.03 Formulate and revise scientific explanations and models using logic and evidence to:• Explain observations.• Make inferences and predictions.• Explain the relationship between evidence and explanation.

(RBT B2, B6, C2, C6)

Use questions and models to determine the relationships between variables in investigations.

Use evidence from an investigation to support a hypothesis.

1.04 Apply safety procedures in the laboratory and in field studies:• Recognize and avoid potential hazards.• Safely manipulate materials and equipment needed for scientific investigations.

(RBT B3, C3)

Predict safety concerns for particular experiments

o Electricityo Projectiles

Relate physics concepts to safety applications such as:

o Transportation: seat belts, air bags, speed…

Short circuits, circuit breakers, fire hazards

6.01 Investigate and analyze energy storage and transfer mechanisms:• Gravitational potential energy.• Elastic potential energy.• Thermal

Develop the concept of energy as the ability to cause change.

Describe energy transfer and storage in different physical systems, including but not limited to those involving gravitational potential energy, elastic potential energy, thermal energy, and kinetic energy.

Apply proportional reasoning to the relationship between an object’s kinetic energy and the object’s mass and velocity

according to the equation:

Physics- Unit 5 DRAFT 2

energy.• Kinetic energy. (RBT C3)

Analyze changes in gravitational potential energy when an object’s mass and/or height change:

Apply proportional reasoning to the relationship between a spring’s potential energy and its deformation, x, according to

the equation:

Show that PEs = area under a graph of Force vs. deformation (stretch or compression), where . The spring constant k is equal to the slope of the graph and is called the elastic constant.

Analyze conceptually that thermal energy increases when an object’s temperature increases.

Apply the idea that energy can be transferred when objects interact. (See work under 6.02)

Express and apply the idea that in all situations, energy tends to dissipate throughout the environment.

Express the concept of energy conservation by applying the idea that energy can be stored and transferred, but cannot be created or destroyed.

Express an understanding of the conservation of energy in words as well as charts, diagrams and graphs.

6.02 Analyze, evaluate, and apply the principle of conservation of energy.(RBT B2, C4, C3)

Use conceptual analysis and mathematical formulas for energy to determine amounts of energy stored as kinetic energy, elastic potential energy, gravitational potential energy, and amounts of energy transferred through work.

Analyze and investigate the relationship among kinetic, potential, and other forms of energy to see that total energy is conserved. (pendulum in various positions, ball in flight, stretching a rubber band, hand generator, turbine)

Solve problems relating the amounts of energy stored and transferred applying the principle of conservation of energy.

6.03 Analyze, evaluate, and measure the transfer of energy by a force.• Work.• Power.(RBT B2, C3, C6)

Identify work as the transfer of energy by a force acting through a distance, when that force acts in the direction of motion of the object:

Recognize that work is equal to the area under a force vs. distance graph.

Define power as the rate of transferring energy or the rate of doing work.

Use the power equation to solve mathematical problems

involving transfer of energy through work:

Recognize that a force must cause displacement in order for work to be done.

6.04 Design and conduct investigations of:

Verify through investigations the conservation of energy in situations involving transfer of energy among kinetic energy, elastic potential energy and gravitational potential energy.

Physics- Unit 5 DRAFT 3

• Mechanical energy.• Power.(RBT C4, C6)

Investigate power.

Honors Honors topics: Catapult construction

VI. English Language Development Objectives (ELD) Included:NC English Language Proficiency (ELP) Standard 4 (2008) for Limited English Proficiency Students (LEP)- English Language learners communicate information, ideas, and concepts necessary for academic success in the content area of science.

Suggestions for modified instruction and scaffolding for LEP students and/or students who need additional support are embedded in the unit plan and/or are added at the end of the corresponding section of the lessons. The amount of scaffolding needed will depend on the level of English proficiency of each LEP student. Therefore, novice level students will need more support with the language needed to understand and demonstrate the acquisition of concepts than intermediate or advanced students.

VII. Materials/Equipment Needed: Most of the activities for this unit use inexpensive and simple materials. Those materials can be found here.

wooden block with an eye bolt attached

Spring scale

Meter stick Flat board (to be used as ramp)Books to prop ramp Electronic balanceMasking tape Loose masses

VII. Detailed Content Description:

Please see the detailed content description for each objective in the biology support document. The link to this downloadable document is in the Physics Standard Course of Study at:

http://www.ncpublicschools.org/curriculum/science/scos/2004/27physics

VIII. Unit Notes:

Physics- Unit 5 DRAFT 4

Overview of Unit Four:This unit is focused on the concept of energy. Students will learn about the relationships between force, displacement, work, and energy.

The Unit Guide below contains the activities that are suggested to meet the Standard Course of Study (SCOS) Goals for Unit Four. The guide includes activities, teacher notes on how to implement the activities, and resources relating to the activities which include language objectives for LEP (Limited English Proficient) students. Teachers should also consult the Department of Public Instruction website for English as a Second Language at: http://www.ncpublicschools.org/curriculum/esl/ to find additional resources. If a teacher follows this curriculum (s)he will have addressed the goals and objectives of the SCOS. However, teachers may want to substitute other activities that teach the same concept. Teachers should also provide guided and independent practice from the textbook or other resources.

Physics Support DocumentTeachers should also refer to the support document for Physics at http://www.ncpublicschools.org/curriculum/science/scos/2004/27physics for the detailed content description for each objective to be sure they are emphasizing the specified concepts for each objective.

Reference TablesThe North Carolina Physics Reference Tables were developed to provide essential information that should be used on a regular basis by students, therefore eliminating the need for memorization. It is suggested that a copy be provided to each student on the first day of instruction. A copy of the reference tables can be downloaded at the following URL:

http://www.ncpublicschools.org/docs/curriculum/science/scos/2004/physics/referencetables.pdf

Essential Questions for Unit FourEssential questions are those questions that lead to student understanding. Students should be able to answer these questions at the end of an activity. Teachers are advised to put these questions up in a prominent place in the classroom. The questions can be answered in a journal format as a closure.

1. Explain how the direction of motion affects work.2. What process can be used to calculate the work done on an object by a force

at an angle with the displacement?3. Explain the energy principles used by various methods of generating

electricity.4. Describe the transformations of energy during a bungee jump.5. Calculate an object’s final velocity based on its initial potential energy.6. Develop a procedure to find the relationship between work and kinetic energy.

Physics- Unit 5 DRAFT 5

7. Analyze the use of conservation of energy in a catapult or trebuchet.

Modified Activities for LEP StudentsThose activities marked with a have a modified version or notes designed to assist teachers in supporting students who are English language learners. Teachers should also consult the Department of Public Instruction website for English as a Second Language at: http://www.ncpublicschools.org/curriculum/esl/ to find additional resources.

Computer Based ActivitiesSeveral of the recommended activities are computer based and require students to visit various internet sites and view animations of various biological processes. These animations require various players and plug-ins which may or may not already be installed on your computers. Additionally some districts have firewalls that block downloading these types of files. Before assigning these activities to students it is essential for the teacher to try them on the computers that the students will use and to consult with the technology or media specialist if there are issues. These animations also have sound. Teachers may wish to provide headphones if possible.

Web ResourcesThe web resources provided on this page were live links when the unit was designed. Please keep in mind that as individuals make changes to websites, it is possible that the websites may become inactive. These resources are provided to supplement the activities in the unit. Some of the resources can be used as to supplement your teacher-led discussions by projecting them for the class. Other activities require students to have access to computers.

WEB RESOURCES FOR WORK AND ENERGYSource Description

http://www.article19.com/shockwave/ph.htm “Powerhouse” is a simulation that allows students to see the energy consumed by different appliances in the home and to calculate the cost of the appliance.

http://www.learner.org/interactives/parkphysics/coaster/

Design a roller coaster and observe energy concepts in action.

http://www.glenbrook.k12.il.us/gbssci/phys/Class/energy/u5l2c.html

A web source that looks at the concept of Conservation of Energy through bar graphs.

http://surendranath.tripod.com/Applets/Dynamics/Coaster/CoasterApplet.html

Conservation of energy is applied to a track with a vertical loop in this animation.

http://nces.ed.gov/nceskids/createagraph/default.aspx?ID=b2c5a372d2f74500b34a7d3716f16a4b

Great resource for creating different types of graphs illustrates concept of area under a curve as needed for force

Physics- Unit 5 DRAFT 6

vs. position graphs. http://www.glenbrook.k12.il.us/gbssci/phys/Class/energy/U5L1a.html

This is an excellent site for basic concepts of work and energy.

http://hyperphysics.phy-astr.gsu.edu/hbase/balls.html#c1

This incredible site provides a video of “Newton’s Cradle” and the background of conservation of energy for this device.

http://id.mind.net/~zona/mstm/physics/mechanics/energy/energy.html

This site provides not only background on energy but word games to reinforce concepts.

http://galileo.phys.virginia.edu/Education/outreach/8thGradeSOL/EnergyBallFrm.htm

A very good lesson plan provides connections to a bouncing ball and energy topics.

http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/energy/pe.html

A simulation provides the background for the energy conversions in a simple pendulum.

http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/energy/se.html

This reliable source looks at energy transformation in downhill skiing.

http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/energy/ce.html

This reliable source looks at energy transformation on a roller coaster.

http://scientificsonline.com/product.asp?pn=3053617&bhcd2=1217543856

“The Drinking Bird” is a great motivator in looking at other types of energy rather than mechanical energy.

http://www.funderstanding.com/k12/coaster/index.html

This site offers students the opportunity to design a roller coaster using energy concepts

http://www.fwee.org/walktour/ A site relates physics to hydro plants applies the concepts of energy.

http://schools.matter.org.uk/Content/HookesLaw/index.html

This site explores Hooke’s Law and connects the concept of energy to spring motion.

http://www.wku.edu/pads/exercise.php?id=ggfmkqffmlgqooyfgqmmlag

Students create energy bar graphs for a given problem with this online source.

http://www.wku.edu/pads/exercise.php?id=oaylzqyoagrqggkolrqgmyglo

Students create energy bar graphs for a given problem with this online source.

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

Using a concept map, this site exposes students to many energy applications.

http://ocw.mit.edu/OcwWeb/Physics/8-01Physics-IFall1999/VideoLectures/index.htm

Video lectures illustrate energy concepts in varied ways.

http://phun.physics.virginia.edu/demos/hopper.html

A “popper” experiment excites students to explore energy concepts.

http://www.wfu.edu/physics/demolabs/demos/avimov/bychptr/bychptr.htm

Wake Forest University offers high quality videos illustrating energy concepts through demos.

http://apwww.smu.ca/demos/ As another excellent source of videos for energy demos this site is excellent.

Physics- Unit 5 DRAFT 7

http://paer.rutgers.edu/PT3/ This is a site for physics teaching resources on energy from Rutgers University.

http://jersey.uoregon.edu/vlab/PotentialEnergy/index.html

This site provides a lesson on kinetic and potential energy.

http://ed.fnal.gov/projects/labyrinth/games/warpspeed/race_for_energy/activity.html

High energy resource relates to atomic particle research.

http://www.re-energy.ca/t-i_windbuild-1.shtml A site relates physics to generation of energy using wind and applies the concepts of energy.

http://www.re-energy.ca/t_renewablebasics.shtml

A site relates physics to generation of energy using solar sources and applies the concepts of energy.

http://www.re-energy.ca/t_waterpower.shtml A site relates physics to generation of energy using hydro sources and applies the concepts of energy.

http://www.compadre.org/Repository/document/ServeFile.cfm?ID=3812&DocID=120

Unrestricted lab document connects the simple pendulum to energy concepts.

http://www.myphysicslab.com/spring1.html Using this simulation, students can see the transfer of energy in a vibrating spring.

http://www.re-energy.ca/t-i_solarheatbuild-1.shtml#test_it

The instructions for building a solar oven are included as a possible energy project.

http://www.fifeschools.com/cjh/staff/laker/toyota2006.htm

A teacher site uses “Hot Wheels Physics” as a grant opportunity.

http://monet.physik.unibas.ch/~elmer/pendulum/index.html

This site presents advanced exploration for the simple pendulum and energy concepts.

http://www.wfu.edu/academics/physics/video/lecture.html

Wake Forest University offers high quality videos illustrating energy concepts through lectures.

http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/energy/au.html

Using this link explores conservatives forces through energy concepts

http://www.ngsir.netfirms.com/englishhtm/Work.htm

Explore energy concepts on an incline plane.

X. Global Content: Aligned with 21 st Skills: One of the goals of the unit plans is to provide strategies that will enable educators to develop the 21st Century skills for their students. As much as students need to master the NCSOS goals and objectives, they need to master the skills that develop problem solving strategies, as well as the creativity and innovative thinking skills that have

Physics- Unit 5 DRAFT 8

become critical in today’s increasingly interconnected workforce and society. The Partnership for 21st Century Skills website is provided below for more information about the skills and resources related to the 21st Century classroom.

http://www.21stcenturyskills.org/index.php?option=com_content&task=view&id=27&Itemid=120

GLOBAL CONTENT—Goal Six

NC SCS Physics

21st Century Skills Activity

Communication Skills1.01, 6.01, Conveying thought or opinions

effectivelyAnalysis questions in all labs

6.01, 6.02 When presenting information, distinguishing between relevant and irrelevant information

Data analysis in all labs

6.01,6.02, 6.03,6.04

Explaining a concept to others Analysis questions in all labs/ Team Quiz

6.01,6.02, 6.03,6.04

Interviewing others or being interviewed

Team Quiz

Computer Knowledge6.01,6.02, 6.03,6.04

Using word-processing and database programs

Energy Poster, Work/KE Lab Report

6.01,6.02, 6.03,6.04

Developing visual aids for presentations

Energy Poster

6.01,6.02, 6.03,6.04

Using a computer for communication Energy Poster, Work/KE Lab Report

6.01,6.02, 6.03,6.04

Learning new software programs Lab simulation from PhET ( Energy Skate Park)

Employability Skills6.01,6.02, 6.03,6.04

Assuming responsibility for own learning

All lab activities

6.01,6.02, 6.03,6.04

Persisting until job is completed All lab activities and team Quiz

6.01,6.02, 6.03,6.04

Working independently Energy Poster

6.01,6.02, 6.03,6.04

Developing career interest/goals Energy Poster

6.01,6.02, 6.03,6.04

Responding to criticism or questions Team Quiz

Information-retrieval Skills6.01,6.02, 6.03,6.04

Searching for information via the computer

Energy Poster, PhET Simulation, Catapult Project

6.01,6.02, 6.03,6.04

Searching for print information Energy Poster

6.01,6.02, Searching for information using Energy Poster, Team Quiz

Physics- Unit 5 DRAFT 9

6.03,6.04 community, membersLanguage Skills- Reading

6.01,6.02, 6.03,6.04

Following written directions All labs in the unit

6.01,6.02, 6.03,6.04

Identifying cause and effect relationships

All labs in the unit

6.01,6.02, 6.03,6.04

Summarizing main points after reading Energy Poster

6.01,6.02, 6.03,6.04

Locating and choosing appropriate reference materials

All lab activitiesEnergy Poster

6.01,6.02, 6.03,6.04

Reading for personal learning Energy Poster

Language Skills- Writing6.01,6.02, 6.03,6.04

Organizing and relating ideas when writing

“Explain” and “Evaluate” sections in all lab activities, Lab Report

6.01,6.02, 6.03,6.04

Proofing and Editing Energy Poster, Lab Report

6.01,6.02, 6.03,6.04

Synthesizing information from several sources

Energy Poster, Lab Report

6.01,6.02, 6.03,6.04

Documenting sources Energy Poster

6.01,6.02, 6.03,6.04

Developing an outline Energy Poster

6.01,6.02, 6.03,6.04

Writing an outline Energy Poster

6.01,6.02, 6.03,6.04

Writing to persuade or justify a position All lab activities

6.01,6.02, 6.03,6.04

Creating memos, letters, other forms of correspondence

Energy Poster

Teamwork6.01,6.02, 6.03,6.04

Taking initiative All lab activities and “Team Quiz”

6.01,6.02, 6.03,6.04

Working on a team All lab activities and “Team Quiz”

Thinking/Problem-Solving Skills6.01,6.02, 6.03,6.04

Identifying key problems or questions All lab activities and “Team Quiz”

6.01,6.02, 6.03,6.04

Evaluating results All lab activities and “Team Quiz”

Physics- Unit 5 DRAFT 10

Teacher notes for Intro to Work Lab

Language (ELP) Objective for LEP Students:

Physics- Unit 5 DRAFT 11

ENGAGE:Have a student put on a backpack full of books and walk around the classroom. Ask the class how much work this person is doing. Student answers will vary. Have them draw a free body diagram of the backpack, showing all forces acting on it. Ask for a student volunteer to come put their diagram on the board, and have the class discuss the diagram. The correct diagram should only have two forces; the downward force from gravity, and the upward force exerted by the student’s shoulders. Lead students through a discussion of the fact that since there is no horizontal force, the student is doing no work. Likewise, since the bag is not moving vertically, gravity is also not doing any work.EXPLORE:Students will explore the ideas of work, force, and displacement during the lab activity.EXPLAIN: The analysis questions give students an opportunity to explain the connections between direction of force, displacement, and work. The collaborative nature of lab work also allows students to discuss concepts and explain processes to one another.ELABORATE:The extension to this lab provides an opportunity for students to build on their knowledge by designing their own procedure to determine the work done by a force applied at an angle to the displacement. EVALUATE:Upon completion of this activity, students should be encouraged to write about the concepts they explored. A quickwrite or Think/Pair/Share activity is an excellent way to allow students to judge their own understanding of the concepts.

Lab: Intro to WorkPurpose: to determine the amount of work done to an object in various scenariosMaterials:

wooden block with an eye bolt attachedspring scaleloose masses meter stick

flat board to be used as a rampbooks to prop rampelectronic balancemasking tape

Physics- Unit 5 DRAFT 12

Procedure:1. Weigh the block using the electronic balance. Record the mass in

kilograms.

Part A2. On a smooth, horizontal surface, mark a starting line and a stopping point

with masking tape.3. Attach the spring scale to the eye bolt, place the block at the starting line,

and drag it horizontally at constant velocity with the spring scale. Be sure to keep the force on the scale as constant as possible. Record the force and the distance traveled.

Part B4. Using the spring scale, lift the block 1.5 meters off of the ground at a

constant velocity. Be sure to keep the force on the scale as constant as possible. Record the force and the distance traveled.

Part C5. Using the books, set up a ramp on the floor. Record the lengths of each

leg and the hypotenuse of the ramp. 6. Place the block at the bottom of the ramp. Holding the spring scale

parallel to the surface of the ramp, drag the block to the top of the ramp at constant velocity. Record the force used.

7. Draw a free body diagram showing all forces acting on the block as it is pulled up the ramp.

DataMass of the block : _______________kg

Part A Part BDirection of force

Distance Traveled (m)

Magnitude of force (N)

Part CHypotenuse (m)

Height (m) Length (m) Force (N)

Free body diagram:

Analysis1. Calculate the work done by gravity in Part A. Explain your answer. (Hint:

think about the relationship between work, direction of force, and displacement)

2. Calculate the work done by the applied force in Part A. Explain your answer.

3. Calculate the work done by gravity in Part B. Should the work be positive or negative? Explain.

4. Calculate the work done by the applied force in Part B. Should it be positive or negative? Explain.

5. In Part C, which distance should be used to calculate the work done by gravity? Should the same distance be used to calculate the amount of work done by the applied force? Explain your answers.

6. Calculate the work done by gravity, and the work done by the applied force. Be sure to use the appropriate signs.

7. Explain how you could calculate the work done by friction in each part of this lab. Would this process be different if the object was accelerating? Explain.

ExtensionDesign a procedure to determine the amount of work done to an object by a force that is at an angle with the horizontal (examples: a sled being pulled across the ground or a lawnmower being pushed).

TEAM QUIZ—WORK AND ENERGY

Language (ELP) Objective for LEP Students:

PROCEDURE:1. Cut up card sheet. If desired, staple each Quiz to a note card to make them more durable for use year after year.2. Give each student a copy of the problem.3. Explain how to fill in blanks. Each student selects a row and works each part of the problem with the given data.4. Explain the difference between individual totals and team totals. Individual totals are the sum of the answers to all parts “a”-“e” and Team Total is the sum of all individual totals.5. Emphasize that all work must be shown for credit and that work as well as answers will be checked.The spreadsheet is included so that individual answers may be checked.

INTRODUCTION : Using the Team Quiz idea allows students to work together to understand application of equations to problem solving. The teacher creates teams of 2 to 4 students. Included are Team Quiz cards for classes from size 2 to 33. The teacher selects the cards to fit the class enrollment. In addition, if a student is absent then the flexibility is there. Every student gets a copy of the problem but each fills in blanks 1 and 2 with unique numbers. In this way, students are encouraged to work together without the risk of copying. ENGAGE: Remind students that working together is an important part of learning physics EXPLORE: Students must explore a method to solve the various parts of the problem.EXPLAIN: Working together, students explain to each other methods of problem solving.ELABORATE: The problem structure has parts that force students to elaborate on relationships with work and energy.EVALUATE: Students evaluate the correctness of their method using the team total.

Team Quiz—Work and Energy Name:A 200 kg load is lifted vertically a distance of _______ meters with an acceleration of _________ meters/second2 upward by a rope attached to the load. Determine:a) The tension in the rope: __________

b) The work done by the rope on the load:__________

c) The work done by gravity on the load: ____________

d) The net work done on the load by all the forces acting: ______________

e) The final speed of the load (assuming that the load started at rest): ______________

Your Individual Total: ______________________

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

1 1 2 41 2 3 31 3 5 21 4 4 5

Team

Total = 29459

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

2 1 1.2 1.62 2 2.2 1.82 3 3.2 2.22 4 4.2 2.4

Team

Total = 18653

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

3 1 1.4 2.13 2 2.4 2.33 3 3.4 2.53 4 4.4 2.7

Team

Total= 21311

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

4 1 1.6 5.34 2 2.6 5.14 3 3.6 4.94 4 4.6 4.7

Team

Total = 36262

TEAM QUIZ WORK TEAM QUIZ WORK

Team

Person

distance-m

acceleration m/s^2

5 1 7 35 2 5 3.25 3 3 3.45 4 2 3.6

Team

Total= 32260

Team

Person

distance-m

acceleration m/s^2

6 1 5 46 2 4 4.26 3 3 4.46 4 2 4.6

Team

Total= 34982

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

7 1 7 1.87 2 6 27 3 5 2.3

Team Total = 21555

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

8 1 6 38 2 4 48 3 3 5

Team Total = 27897

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

9 1 3.2 49 2 3.7 39 3 3.9 2

Team Total =20373.72

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

10 1 6 1.110 2 8 1.5

Team Total = 11888.53

TEAM QUIZ WORKTeam

Person

distance-m

acceleration m/s^2

11 1 7 4.211 2 5 4.8

Team Total = 27094.60

TEAM QUIZ WORK

ANSWERS:TEAM 1Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

Individual total

2760 5520 -3920 1600 4.00 5964.002560 7680 -5880 1800 4.24 6164.24

2360 11800 -9800 2000 4.47 6364.472960 11840 -7840 4000 6.32 10966.32

Team Total 29459.04

TEAM 2Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s  

2280 2736 -2352 384 1.96 3049.962320 5104 -4312 792 2.81 3906.812400 7680 -6272 1408 3.75 5219.752440 10248 -8232 2016 4.49 6476.49

Team Total 18653.02

Team 3Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2380 3332 -2744 588 2.42 3558.422420 5808 -4704 1104 3.32 4631.322460 8364 -6664 1700 4.12 5864.122500 11000 -8624 2376 4.87 7256.87

Team Total 21310.75

TEAM 4Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

3020 4832 -3136 1696 4.12 6416.122980 7748 -5096 2652 5.15 8289.152940 10584 -7056 3528 5.94 10001.942900 13340 -9016 4324 6.58 11554.58

Team Total 36261.78

TEAM 5Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2560 17920 -13720 4200 6.48 10966.482600 13000 -9800 3200 5.66 9005.662640 7920 -5880 2040 4.52 6724.522680 5360 -3920 1440 3.79 5563.79

Team Total 32260.45

TEAM 6Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2760 13800 -9800 4000 6.32 10766.322800 11200 -7840 3360 5.80 9525.802840 8520 -5880 2640 5.14 8125.142880 5760 -3920 1840 4.29 6564.29

Team Total 34981.55

TEAM 7Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2320 16240 -13720 2520 5.02 7365.022360 14160 -11760 2400 4.90 7164.902420 12100 -9800 2300 4.80 7024.80

Team Total 21554.71

TEAM 8Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2560 15360 -11760 3600 6.00 9766.002760 11040 -7840 3200 5.66 9165.662960 8880 -5880 3000 5.48 8965.48

Team Total 27897.13

TEAM 9Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2760 8832 -6272 2560 5.06 7885.062560 9472 -7252 2220 4.71 7004.712360 9204 -7644 1560 3.95 5483.95

Team Total 20373.72

Team 10Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2180 13080 -11760 1320 3.63 4823.632260 18080 -15680 2400 4.90 7064.90

Team 11888.53

Total

Team 11Tension

- NWork of rope -J

Work of gravity-J Net work-J

Final speed-m/s

2800 19600 -13720 5880 7.67 14567.672920 14600 -9800 4800 6.93 12526.93

Team Total 27094.60

ENERGY POSTER PROJECT Language (ELP) Objective for LEP Students:

Possible Web Sites: http://home.nc.rr.com/enloephysics/geo/Geothermal.htmlhttp://home.nc.rr.com/enloephysics/hydro/page1.htmlhttp://home.nc.rr.com/enloephysics/solar/index.htmlhttp://home.nc.rr.com/enloephysics/wind.htmhttp://www.gcse.com/energy/energy_sources.htmhttp://fusedweb.llnl.gov/CPEP/ http://www.youtube.com/watch?v=Z_DDj2Q89ichttp://www.bbc.co.uk/schools/ks3bitesize/science/physics/energy_transfer_intro.shtmlhttp://www.emints.org/ethemes/resources/S00002115.shtmlhttp://www.think-energy.com/ThinkEnergy/Default.aspx

Description: Students will create an energy poster on one of the following topics 1) energy from wind turbines 2) energy generated by hydro plants 3) geothermal energy 4) solar energy 5) energy generated by fission reactors 6) energy generated by fusion reactions 7) solar energy and 8) energy generated by tidal power. Physics energy principles must be featured on the poster as illustrated by the attached rubric.ENGAGE: Use the ongoing discussion about off-shore drilling that North Carolinians may have to eventually vote on to broach the issue of energy sources. Ask students to vote on whether they are in favor of off shore drilling.EXPLORE: After the vote, ask students to list ways of generating energy. Add to the list so that all of the eight possibilities above are listed.EXPLAIN: The poster project provides the student with the opportunity to explain the connections of physics energy concepts to the energy production methods mentioned above in the introduction.ELABORATE: Students have the opportunity to elaborate on application of physics principles to creating energy for consumption. EVALUATE: The rubric allows both students and teacher to evaluate the project.

ENERGY PRODUCTION and PHYSICS CONCEPTS

NAME: _____________________________________________

CATAGORY 4 3 2 1Physics Content At least four

major physics work/energy concepts are applied

Three major physics work/energy concepts are applied

Two major physics work/energy concepts are applied

One major physics work/energy concept is applied

Energy Production Content

The method of energy production is clearly explained and illustrated

The method of energy production is clearly explained or illustrated

The method of energy production is explained or illustrated somewhat clearly.

The method of energy production is explained or illustrated but not clearly

GRAPHICS OR ILLUSTRATIONS

Pictures are well chosen for relevance and all are documented as to source.

Pictures are well chosen for relevance and most are documented as to source

Pictures are well chosen for relevance and some are documented as to source

Pictures are well chosen for relevance but none are documented as to source

NEATNESS, ORGANIZATION, AND GRAMMAR

The poster is very well organized, very attractive and has no spelling or grammar mistakes.

The poster is well organized, attractive and has no more than 2 spelling or grammar mistakes.

The poster is organized, attractive and has no more than 3 spelling or grammar mistakes.

The poster is somewhat organized, attractive and has more than 3 spelling or grammar mistakes.

ENERGY SKATE PARK LAB SIMULATION Language (ELP) Objective for LEP Students:

ANSWERS TO QUESTIONS:

1. Student answer2. Potential energy decreases.3. Height is distance above a chosen reference line.4. Student answer.5. As potential energy decreases along the path, speed increases and

therefore kinetic energy increases.6. Since the mass changes then both potential energy (mgh) and kinetic

energy (1/2 mv2) changes.7. Total mechanical energy is constant.8. Total mechanical energy decreases.9. Student answer10. a) height above reference line b) student answer c) student answer11. a) student answer b) the force of gravity

This activity is an online simulation that may also be downloaded and place on computers that are not online. http://phet.colorado.edu/simulations/sims.php?sim=Energy_Skate_Park

ENGAGE: Introduce the simulation using an LCD projector if possible. The simulation itself is very visually engaging. Show how to build the ramp and mark the path. Practice this yourself so that you may help students if questions arise.

EXPLORE: Students explore the concept of energy conservation and mechanical energy conversion in an open ended method by building a skate park ramp.

EXPLAIN: The questions in the activity focus on explanations for decisions that are made in the simulation.

ELABORATE: Students consider the affect of moving the park to another planet in our solar system.

EVALUATE: Data is collected and potential energy and kinetic energy is calculated as well as total energy.

SKATE PARK ENERGY LAB NAME:

Use the following URL.http://phet.colorado.edu/simulations/sims.php?sim=Energy_Skate_Park

Your first challenge is to build a good skate park ramp that is safe and will not hurt the skater! Cut off friction (uncheck Thermal Energy) to start with as you create your ramp. Check “Show Grid” so you may draw your final design on the grid below.

1. What is your starting height? _______________ m.

2. Potential energy is related to your starting height but the reference point is a decision that must be made in every situation that involves energy. Click “Show Path” and also click “Potential Energy Reference”. What happens to your potential energy when you move the “Potential Energy Reference” line upward? Check several points to see.

3. What exactly does the word “height” mean in relationship to the skater?

4. What is your starting speed? ____________ m/s5. Kinetic energy is related to the speed of the skater. How does a decrease

in potential energy at different points along the path affect kinetic energy? (Assume an unchanging starting point.)

6. Change the skater type. How does this affect potential energy? Kinetic energy? Why?

7. Both potential energy and kinetic energy are classified as “Mechanical Energy”. Pick several points on your path and total the potential energy and kinetic energy. What do you observe?

Height = 12.00 mSpeed = 1.83

Measuring Tape Potential Energy Reference

Show GridShow path clear

Please Note: You may take measurements by using the “Show Path” button. Purple dots will appear to show the path. Click on a purple dot to see the numbers associated with the point. Clear the path when you must take new measurements.

8. Click the box beside friction. Let’s see what happens to the total mechanical energy (the sum of potential and kinetic energy) when friction is part of the system. What did you observe?

9. Consider the following situation: Put a Skater on your track, select Show Path and display the purple dot data for your starting point. Record that data below. You may use the measuring tape to measure distances.

10.How could you predict the values for another place on the track? a. Describe what you would have to measure.

b. Show your calculations for each value of the point you chose: PE, TE, KE, speed.

PE:

TE:

KE:

SPEED:

Energy Reference Line Position (m)

Height from Reference Line(m)

PE (J) KE (J) Speed (m/s)

c. Use the simulation to check the values you calculated. Record your calculated results and the results from the simulation below.

Calculated PE = TE = KE = Speed =

Simulation PE = TE = KE = Speed =

11. a. Describe what you think will change in your calculations if you move the Skater to Jupiter.

b. What would be the biggest change on Jupiter that affects the skater’s energy?

TEACHER KEY AND RESOURCES for HOT WHEELS PHYSICS Language (ELP) Objective for LEP Students:

This lab activity focuses on conservation of energy, central forces in a loop, and efficiency of a system.

Teacher Key to Hot Wheels ® Physics: This is intended to be a very open ended activity. Remind students that conservation of energy is different than conservation of mechanical energy (kinetic energy and gravitational potential energy). Energy is conserved in this toy but mechanical energy is not conserved. The percent efficiency is the output mechanical energy divided by the input mechanical energy and the quotient is multiplied by 100. The starting point of the car gives us input energy using mgh1. Measure the height from the low point of the track. The output energy is measured at the top of the loop and has both kinetic energy and gravitational potential energy mgh2 (measured from the bottom of the track).

The math for calculating the release height so that the car just makes the loop follows.

Engage: Take a “Hot Wheels®” car and roll it along the floor or a lab table. Then ask the question “I wonder how much physics we can learn by studying Hot Wheels® Tracks and Cars? Anyone have any suggestions about the physics involved in the Hot Wheels® Tracks and Cars System? If we can come up with three physics applications then we will do a lab with Hot Wheels® Physics.” List all physics applications (types of forces, friction, and types of energy on the board). Explore: Students investigate the efficiency of the track and make predictions about the release height needed to make the circular loop on the track.

Explain:Students explain their choices in the investigation and the results that follow.

Elaborate:Students must improve the efficiency of the system. They may replace the car, lubricate the tracks, or make the tracks more anchored to the table and less flexible.

Evaluate:The question of efficiency is very energy based and very much a “real life application” of physics. It is a point that must be made as energy becomes a more expensive and sought after resource. Students will realize how inefficient most energy transfer systems are when they calculate the efficiency of the Hot Wheels® Tracks/ Car System.

mgh1 + 0 = mgh2 + ½ mv2 (conservation of energy)

-mg – N = -mv2/R (net force equation for car at the top of the loop of radius R)Since the car is going just fast enough to make the loop then N (normal force) =0.

So –mg = -mv2/R.

That means that mv2 =mgR

Putting that back into the energy statement and using h2 = 2R:mgh1= 2mgR + ½ mgR

so theoretically h1 = 2.5 R. In reality h1> 2.5 R

Students will need hints on how to do this.

Sources of “Mattel Hot Wheels G Force” Track Sets (from $12.99- $29.99)

http://astore.amazon.com/hotwheels-20/103-7861526-5919805?%5Fencoding=UTF8&node=7

http://www.boscovs.com/StoreFrontWeb/Product.bos?assortmentDepartmentNumber=6171320&assortmentId=4&itemNumber=23769&type=Product

http://www.sortprice.com/search-BCQ-20-Toy_Cars_and_Vehicles-Hot_Wheels

HOT WHEELS PHYSICS NAME PURPOSE: TO INVESTIGATE ENERGY CHANGES ON A HOT WHEELS® TRACK

Your Challenge: Find the theoretical height from where the Hot Wheels car must be

released to barely get to the top of the loop. Attach your calculations to this lab.

Find the actual height from where the Hot Wheels car must be released to just barely get to the top of the loop.

Measure the total mechanical energy in the system at the release point and at the top of the loop.

Calculate the percent efficiency of the system comparing the release point and the top of the loop.

Improve the percent efficiency of the system and describe how you did so.

Hypothesis: What is your prediction for the release height and the percent efficiency?

State why you predicted this value!

Materials: What do you need? Stopwatches, photogates, motion detectors, etc?

Procedure: What is your plan?

Release Height DataFill in the chart with appropriate labels using only what is necessaryTRIAL

1

2

3

4

5

6

Percent Efficiency Data Fill in the chart with appropriate labels using only what is necessary

TRIAL

1

2

3

4

5

6

DATA: Other (your choice—this chart may not be needed)TRIAL

1

2

3

4

5

6

ANALYSIS: Create two energy questions about this lab and answer them.1.

2.

CONCLUSION: What did you learn about the efficiency of your track/car set? Where is the missing energy? How did you improve your results and by how much did you improve your efficiency?

Energy and Work Lab Activity-- Teacher Guide Language (ELP) Objective for LEP Students:

Note: This activity works with a motion detector and the following devices: a

LabPro, CBL, Pasco Interface, or a direct connect method such as to TI Inspire CAS.Answers to Questions:Calculations: 1) Student answer—as the teacher, visit each lab team several times to make sure data collection follows correct procedure. Remind students that vo is zero and vf is read directly from the velocity, time graph at the time a change in position equals 0.300 m.2) The slope of position, time equals velocity and the slope of velocity, time equals acceleration. Use the data collection software to obtain those slopes. The slope of the velocity, time graph is the best method of finding acceleration using a motion detector. Some students will attempt to use the acceleration, time graph but they will find more variation in that graph.3) Check to see that students convert 30.0 cm to 0.300 m. If students have not seen the unit of energy and work, introduce the “Joule as a kg-m2/s2”.

Engage: The teacher walks at constant velocity carrying a suitcase or another heavy mass with a handle. Ask students to vote (“physics by democracy”) on one of three answers regarding the work that is done. The voting is best done on small pieces of paper which they turn in before you discuss the answer. POSSIBLE ANSWERS: (1) a lot of work because the object is heavy (2) a small amount of work because the object is not moving very fast (3) zero work because the force is perpendicular to the direction of the displacement. THE ANSWER IS NUMBER (3).Explore: Students explore the relationship between kinetic energy and work in the lab activity.Explain: Students answer questions to explain how and what they investigated in the lab activity.Elaborate: Students elaborate the findings of their lab activity in the “extension” part of their lab.Evaluate: Students are asked to assess whether the “work energy theorem” applies to their own data.

Analysis:1) Student answer may be “yes” or “no”. Some possible reasons for a “no” answer is the data collection with the motion detector. Make sure that students do not place the cart too close to the motion detector. That distance varies depending upon the model used so check the specifications that come with the device.2) The acceleration is the same for both.3) See the diagram.

4) For the hanging mass: T – 0.050(9.8) = -0.050 a or 0.050(9.8) –T = 0.050 aFor the cart where mass = M: -T = -Ma or T = MaFriction is ignored for the rolling objects.5) Replace T with Ma in the first equation: Ma - 0.49 = -0.050 a.Group the “a” terms: Ma + 0.050a = 0.49 and factor. So a (M + 0.050) = 0.49.Solve for a: a = [0.49]/ (M + 0.050) where M is the mass of the cart.6) Student answer may include some mention of friction particularly in the pulley. We are also assuming a “no mass” pulley which ignores the energy required to rotate the pulley (and the wheels of the cart). Extension: The kinetic energy increases and the tension increases. Both indicate that more work is done on the cart.

cart

Normal force

Weight of cart

Tension

Weight of hanging mass

Tension

ENERGY and WORK LAB ACTIVITY Name:Background: Kinetic energy is the “energy of motion”. It takes work to create a change in kinetic energy. Using a motion detector and your knowledge of Newton’s Second Law, you are going to investigate the relationship between work and kinetic energy for a cart.Materials: A motion detector with an interface to a data collection system, a dynamics cart, a pulley with clamp, a 50 gram mass, a meter stick and about 1.5 meters of string.How to Start: Place the dynamics cart on the table with the pulley clamped to the edge of the table. The motion detector is placed at the other edge of the table. Your teacher will give you instruction on the use of the motion detector. Connect one end of the string to the dynamics cart and tie the other end to the mass. Make sure the string is the correct length to allow the mass to fall 50.0 cm and the cart will also move 50.0 cm on the table. This diagram shows how to connect the mass to the dynamics cart over the pulley.

Collecting Data: Hold the cart at rest on the table with the mass hanging as shown in the diagram. Start data collection with the motion detector. Once you hear the clicking noise from the motion detector, release the cart. Repeat for a total of 5 trials. Use the position, time graph to find the final velocity after the cart travels 50.0 cm from the initial position. Record your data below. (Your teacher will instruct you in obtaining the velocity graph and the slope of your velocity graph after the cart travels 50.0 cm.) Trial Initial velocity

(m/s)Final velocity

(m/s)Slope of velocity, time- (m/s)/s

1 02 03 04 05 0

Record the mass of your dynamics cart here: _________ (kg)Calculations:

cart

50.0cm

Motion detector

1) Calculate the change in Kinetic Energy (½ mvf2- ½ mvo

2) for all 5 trials. Record results in the table at the bottom of the page. Work area:

2) Using the slope of the velocity, time graph and the cart’s mass, calculate the force acting on the cart by the tension of the string. Record results in the table.Work area:

3) Since Work = Force x Distance (along the line of force), find the work done for the 30.0 cm the cart traveled. Record results in the table.Work area:

TRIAL Change in KE (J)

Force Acting on Cart (N)

Work Done by Force (J)

Absolute Difference Between KE & Work (J)

1

2

3

4

5

Analysis:1. The “Work-Energy Theorem” is an extremely important law in physics. It states that “the total work done on an object equals the change in kinetic energy of the object”. Does your data support this law? If not, where do you feel an error occurred?

2. Compare the acceleration of the cart and the hanging mass.

3. Draw the free body diagrams for the forces acting on the cart and the hanging mass. Assume very low friction.

cart

4. Write the force equations for the forces acting on each of the masses.

5. Solve the equations for the acceleration of the cart. Show work below. Record your answer: calculated value of a= ______ m/s2

6. How does your calculated value of the acceleration compare with the experimental value of acceleration? Elaborate on how you could improve your results!

Extension:How would the work done change over the 50.0 cm distance if the hanging mass increases? Explain:

Teacher notes for Work/Kinetic Energy Lab

Language (ELP) Objective for LEP Students:

What to expect:One common mistake students make during this activity is using

the following equation: v = d/t . If they use that equation to find velocity, they will be finding average velocity. Plugging that in to the KE formula gives average KE, which is undesirable, because it doesn’t reflect the KE of the object once work is completed at the bottom of the ramp. This mistake can be prevented by circulating during the lab and having students explain how they collected and used data. When they tell which velocity equation they used, ask them to point to the spot on the ramp where work is complete and then if that is the velocity at that point. Most students will realize they made a mistake at that point, and will choose a more appropriate equation.

ENGAGE:This activity should be done after students have a good understanding of work, kinetic energy, and potential energy. Tell students that they will be designing their own experiment to determine the relationship between the work done to an object and that object’s change in kinetic energy. The teacher should provide a large variety of materials for use such as: meter sticks, stopwatches, ramps, tennis, golf, or other small balls, and Labpros with motion detectors (if available). Encourage students to ask for any other equipment that they might need.

EXPLORE:Students will use a variety of lab equipment to explore the relationship between work and kinetic energy. As students are working on their experiments, the teacher should circulate between groups asking probing questions to help guide students.

EXPLAIN: The written component of this lab gives students the opportunity to explain the correlation between work and kinetic energy. The collaborative nature of an inquiry based lab also encourages discussion between lab partners.

ELABORATE:Students are asked to suggest ways to improve their procedure in the conclusion of the lab report.

EVALUATE:Have students present their experiments to one another and encourage them to question each other’s techniques. This allows students to self evaluate and recommend improvements to their experimental designs.

To find the correct values for velocity and KE, students should use the following equations: Δd = vit + ½ at2 to find the acceleration of the object down the ramp, then either a =Δv/t or vf2 = vi2 + 2aΔs to find the final velocity. The final velocity can then be used to solve for KE.

Work/Kinetic Energy Lab

Purpose: To design and conduct an experiment to determine the relationship between work and kinetic energy by conducting laboratory experiments.

Allowed materials: meter sticks, stopwatches, steel ball bearings of different sizes, tape, ramps. Other materials must be approved before beginning. You are NOT allowed to use your textbooks. Books will be left in the classroom overnight during this lab.

Requirements: Before beginning, each group must submit a written hypothesis and experimental design. Upon approval, you will conduct at least three trials to obtain data. If, upon analyzing that data, you need to make adjustments to your design, you may then do so. If it becomes apparent that your hypothesis was incorrect, you should continue experimenting until you have proof of a relationship between work and kinetic energy. It is okay if your original hypothesis is incorrect. When you write your lab report, you will have a chance to address your hypothesis as well as any changes that were made to your experiment.

Lab Report: You will be writing a formal report for this assignment. Your report should include the following:

1. Purpose2. Hypothesis3. Materials and methods (this needs to be

written so that I could hand it out as lab instructions for another class)

4. Data and analysis (all data tables and calculations should go here. You should show graphs of all data)

5. Conclusionsa. What is the relationship between work

and kinetic energy?b. Was your original hypothesis correct?c. What changes did you make to your

procedure after the first trial? Why were those changes necessary?

d. What were some sources of error in this lab?

e. How could your experimental design have been improved? Think of ways to reduce error.

Teacher notes for Catapult Project

Language (ELP) Objective for LEP Students:

ENGAGE:Show students pictures or video of catapults and trebuchets in action. Then hand out the instruction sheet for the project. Explain to the students that their mission is to create the most efficient catapult or trebuchet in the class. Be sure to discuss proper safety precautions, such as wearing goggles while working with wood, and suggest that students ask a parent or other adult for help if they will be using power tools.

EXPLORE:Use the simulation at http://www.forgefx.com/casestudies/prenticehall/ph/catapult/catapult.htm to allow students to play with the effects that the spring strength, arm length, and release angle have on the horizontal and vertical distances that the projectile travels.

EXPLAIN: The written component of this project gives opportunities for students to explain how catapults and trebuchets were used, as well as to explain the physics behind them both.

ELABORATE:The competition portion of this project provides an opportunity for students to discuss physics concepts in a practical scenario. Facilitate this discussion by asking students to make predictions about the possible improvements to each design. As the competition continues, they should be able to more accurately predict the performance of each catapult.

EVALUATE:The written component of this project provides a way to gauge student understanding. Students are required to analyze each design and discuss ways to improve them. This analysis provides insight into each student’s level of understanding.

Honors PhysicsCatapult Project

Requirements:

1. Your catapult must be able to launch a tennis ball at least 5 feet horizontally from the starting point.

2. The catapult must be finished and ready to go when you come in to class on the competition date. This means that all parts should be put together, glue should be dry, and you shouldn’t have to do anything to it except place the tennis ball on it and trigger the catapult. Incomplete projects will result in a major loss of points.

3. Points will be deducted if the catapult falls apart after the first launch.

4. No slingshots. You may build a catapult or a trebuchet.5. Each team will get three trials. We will use the data from

the best trial.6. All catapults must have some sort of trigger mechanism.

Using your hand or foot to bend back the arm is not acceptable.

Due Dates:

1. Design: Blueprints with measurements of top/side views. All aspects of the catapult must be labeled and measured to receive the full 10 points. Due _______________________

2. Catapult Competition: __________________________We will have three competition categories for extra credit:

1. greatest distance2. best design (best construction/most original)3. most efficient design (size vs. distance)

3. Written report: write 1-3 pages on how forces and conservation of energy are demonstrated with a catapult. A bibliography of at least one source needs to be included. This should also include data regarding the competition, analysis of each team’s catapult, and any improvements you would make to your design. Details can be found on the next page. Due ___________________

Catapults will be graded as follows:

1. Blueprints: worth a total of 10 points. These will be graded based on neatness, accuracy, and design. Blueprints should be clearly labeled, drawn to scale, and should show both the top view and the side view of the catapult. The trigger mechanism should be clearly labeled, as well as the method of propulsion and the “basket” for the projectile.

2. Construction: worth a total of 20 points. This will be graded based on the execution of your design. Did you follow your blueprints? If not, did you submit revised plans? Is the catapult neatly built? Quality of construction and sloppiness count here!

3. Projectile launch: worth 20 points. This will be graded based on a comparison between the maximum dimension (length, width, or height) of your catapult and the horizontal displacement of the projectile. If your catapult self-destructs after being used, you will lose points here!

20 points: 10x 15 points: 7x

10 points 4x 5 points: 2x

4. Lab Report: worth 50 points. Include background about catapults and similar devices, as

well as information about their use throughout history. Discuss how this project relates to the different areas of

physics. Be thorough. I can think of at least 5 connections just off the top of my head. Be sure to discuss the energy transformations involved in launching a catapult or trebuchet.

Include detailed instructions about the construction of your catapult. These should have enough detail that someone else could build your catapult using your directions. Be sure to include a discussion of why you chose this particular design.

1. Why did you choose these materials?2. Why did you choose this method of propulsion?3. Why did you choose this trigger mechanism?

Describe the other groups’ catapults, including their propulsion and triggers.

Data from the competition, including the efficiency of each catapult.

Analysis of the results of the competition. Discuss the reasons why certain designs were more successful than others. How could each design be improved to be more efficient?

Explain improvements that could be made to your catapult. Include a sketch. Remember, none of the projects are perfect. They could all be improved!

Assessment Items

1. A student walks 2 m across a level surface at constant velocity carrying a 5N backpack on his back. What is the net work done on the backpack?a. 0 J b. 2.5 J c. 5 J d. 10 J

2. ________________ is the sum of kinetic energy and all forms of potential energy.a. elastic potential energy c. gravitational potential energyb. kinetic energy d. mechanical energy

3. ________________ is the type of energy associated with objects in motion.a. elastic potential energy c. gravitational potential energyb. kinetic energy d. mechanical energy

4. A 25 kg crate rests at the top of a 12 m tall hill. What is the crate’s potential energy?

5. A 55 kg student runs at 8.5 m/s. What is his kinetic energy?

6. If a geyser shoots water at a maximum velocity of 12 m/s, what is the maximum height the water will reach?

7. Using the graph below, calculate the work done on the object.

8. If the work in problem #7 is done in 5.0 seconds, what is the power?9. A 40.0 N crate starting at rest is pushed with a force of 35N

across a 6.0 m distance. The force of friction between the crate and ground is 6.0 N. Using the work-kinetic energy theorem, find the final velocity of the crate.

10. Discuss the energy transformations involved when a tennis racket hits a tennis ball.

Answers:1. a. zero work is done because the force is perpendicular to motion2. d3. b4. 2940 J5. 1987 J6. 1/2mv2 = mgh since the masses are the same, mass cancels out and

½ (12)2 = 9.8 h72 = 9.8hH = 7.3 m

7. Work is the area under the graph, so 4 x4 = 16 N*m8. P = W/t so P = 16/5 = 3.2W9. 40 = mg so mass is 4.0 kg

Fnetd = KEf – KEi since initial velocity is zero, KEi is zero(35-6) x 6 = 1/2(4.0) v2

175 = 2v2

87 = v2

V = 9.3 m/s10. Answers will vary, but should include the following: the racket and ball

initially have kinetic energy, because they are both moving. When they hit, the tennis ball is deformed giving it elastic potential energy which is then converted into kinetic energy as the ball flies away.

Physics- Unit 4 DRAFT 47