gravity unit packet - mr. burrell's 8th grade science...
TRANSCRIPT
Simple Machines Unit Packet
Name: _____________________________ Period: _______
Date:(subject to change) Lesson/Worksheets/Labs: Score:
Every Day Starter Questions (1 box/day) /12
Every Day WS: Simple Machines Unit Vocabulary /50
/(B) or /(A)Lesson: Work & Power
Lab: Work & Power /50
/(B) or / (A)
Lesson: Machines
WS: Bill Nye Simple Machines /24
WS: ID of Machines /16
/ (B) or / (A) Lesson: Mechanical Advantage
Lab: MA of Levers /70
/ (B) or / (A)
Lab: MA of Ramps /40
Lab: MA of Pulley’s /40
Quiz: Simple Machines /24
WS: Simple Machines WA Review /40
Total Unit Points
Being absent does not excuse you from
missing work! It is your responsibility to
get caught up!
Make-up labs will be scheduled during Pride Time if you miss a lab. Make sure you come to
these make up days!
Starter Questions: (3 points each)
/12If you miss a starter question day, the questions are posted to the unit page on the class website after the class is over.
(1 point each written item)Main Principals of Simple Machines
1) Work is only done when the _______________ and _______________ are in the ______
___________________.
2) Power is only about _________________ work gets _____________.
3) Simple machines work by ___________________________ or both of two main
variables: ________________ &/or ____________________
4) As a result of the __________________, an __________________ occurs and work gets
done on an object!
5) What we really want to do is get the _______________________________ as
__________________ as possible.
6) __________________________________ is all about getting the ______________ to
make the job as ______________________________ as possible!
7) The ________________ the ________________________________, the ____________
it is to accomplish the ______________.
______________________________________________________________________________
Vocabulary Terms you need for the test:1) Work
Definition:
What is the formula for work:
What is the unit for work: _______________How much work is done if you push with a large amount of force, but no motion occurs?
2) Power Definition:
Why does a power saw have more “power” than a hand saw?
What is the formula for power: What is the unit for Power: _______
/50If you are missing any part of this worksheet, you can view the lessons on the unit page any time. The answer key will also be
posted on the website after the review day (before the test)
3) Effort Definition:
Give an example of using a machine to travel a distance with less effort than walking:
4) Machine Definition:
Q: Why do we use machines?A:
5) Input Definition: Push or pull that ________________________ to the machine Give an example of a human using Input force:
6) Output Definition: Push or pull _________________________ on the objectGive an example of the output force from a machine as a result of a human’s input force:
7) Lever Definition:
Draw a basic lever (Label the input and output sides):
8) Pulley Definition:
Draw a basic pulley (Label the input and output sides):
9) Incline Plane (Ramp) Definition:
Draw a basic ramp (Label the input and output sides):
10) Wedge Definition:
Draw a basic wedge (Label the input and output sides):
11) Wheel & Axle Definition:
Draw a basic wheel & axle (Label the input and output sides):
12) Compound Machine Definition:
13) Efficient Definition:
14) Mechanical Advantage Definition:
What is the formula for MA:
Materials: stopwatch calculator stairs meter stick
Problem:Can you change the amount of power you use while doing an exercise?
Procedure:
1) This lab will be performed on a single stair step. 2) Predict how your results will change if you step up and down at different speeds.
3) Measure the vertical distance in centimeters from the floor to the top of the step. Convert to meters by dividing by 100 and record this height in the data table.
4) Convert your weight from Pounds to Newton’s: multiply your weight(lbs) by 4.448 = N
5) Calculate the work you do in stepping up onto the step once. Record this in your data table.
6) Have one partner time how long it takes you to do 20 step repetitions performed at a constant speed. Count out loud to help the timer keep track of the number of repetitions. Record the time in your data table. (two feet up & two feet down = one repetition)
7) Calculate the Work and the Power in stepping up onto the step for 20 times “slowly”. Record your results in the data table.
8) Repeat Steps 5 thru 7, but climb the step “faster” than you did the first time. Record the new data in the data table.
9) Switch roles with your partners and repeat Steps 5 thru 7.
10) Record all your data in the data table.
Equations:
Work = Force x Distance (weight is a force & height is a distance)
Power = Work / Time
Predict: How will the power needed and the work performed change when you increase the speed of the repetitions of steps? (2 pts. each)
/50If you miss this lab, make sure you attend the make up session during Pride Time
Power:
Work:
Data Table (1 point each for 36 pts. total)
Weight (N)
Height of stair
(m)
Work for 1 Repetition
(J)
Work for 20 Repetitions (J)
Time for 20 Repetitions (s) Power (W)
Student 1 Slow Repetitions
Student 1 Fast Repetitions
Student 2 Slow Repetitions
Student 2 Fast Repetitions
Student 3 Slow Repetitions
Student 3 Fast Repetitions
Analyze and Conclude (2 pts each for 10 pts. total)
1. Compare the amount of work you did during your first and second trials. Trial 1: Trial 2:
2. Compare the amount of power you produced during your first and second trials.
Trial 1: Trial 2:
3. Compare your results to your prediction: What was the same? What was different that you expected?
4. Describe the amount of effort required for the slow and fast tests:
5. Did you and your partners all do the same amount of work? Did you all produce the same amount of power? Explain your answers.
1) What is a good example of a simple machine you would find on a car?
2) What two things do simple machines help us change?
3) What does a pulley change?
4) A catapult is a good example of what kind of simple machine?
5) What do we call the middle of a lever?
6) What must you have in order to make a lever?
7) A ramp is used instead of a ladder because it spread what out?
8) If we use a ramp to raise a large object instead of picking it straight up, we would be using less what with the ramp?
9) A spiral staircase is a lot like what kind of simple machine?
10) What are some examples of what a screw can lift (jack)?
/24If you miss this video, it can be viewed either on You Tube or by checking it out of the library during Pride Time
11) What makes the famous San Francisco streetcars go?
12) If a pulley can enable you to use ½ the normal effort to lift a load, what could you do if you only wanted to use ¼ the normal effort to do the same work?
Observe the cartoon on the next page. Identify each simple machine represented in the machine. Your choices of machines will be: Lever, inclined plane, pulley, wedge, screw, wheel & axel, and pendulum (not really a simple machine, but will be ok in this worksheet)
A. _________________________________________________
/16
B. _________________________________________________
C. _________________________________________________
D. _________________________________________________
E. _________________________________________________
F. _________________________________________________
G. _________________________________________________
H. _________________________________________________
I. __________________________________________________
J. __________________________________________________
K. _________________________________________________
L. _________________________________________________
M. _________________________________________________
N. _________________________________________________
O. _________________________________________________
P. _________________________________________________
Levers are simple machines that consist of a rigid bar that is free to rotate around a fixed point. This fixed point is called a “fulcrum.”
There are three main types of levers: First class: Second Class: Third Class:
/70If you miss this lab, make sure you attend the Pride Time make up session.
Purpose:
In this lab you will be determining the actual mechanical advantage of levers when you adjust the fulcrum, mass and force.
Mechanical Advantage Equation:
MA= Output ForceInput Force
Materials:-1 Meter stick -1 Fulcrum Stand-1 500 g mass -2 Hanger Brackets-1 20 N Force meter -1 Middle Bracket
Procedure: 1) Set up your machine as indicated by the diagrams (on the back side of this page).2) Get your data3) Repeat for all the rest of the setups.4) Record all you data in the data table below:
Prediction: (2 pts. Each) 1) Which lever setup will give you the greatest mechanical advantage (predict)?
2) How many Newton’s (N) are required to lift a 500 gram mass: _________
3) What number represented a “basic” Mechanical Advantage?
First Class Lever (1 point each)
Fulcrum Position (cm)
Output Force (N)
Input Force (N)
Mechanical Advantage:
Effort (Circle One):
Legend Key: Input Force Mass Fulcrum
50 cm
0 cm 100 cm
On the levers to the right, use colored pencils and color over the input side yellow. And color over the
output side green! (two points each)
50 cmXXXXXXXXXXXX
30 cm More Less
70 cm More Less
1) In order to make the MA “better”, what did you do with the fulcrum?
2) Which side of the lever had to be longer (Input or Output) for the “better” MA?
3) What happened to the MA when the Input side was SHORTER than the Output side?
Second Class Lever (use your finger to hold the lever on the fulcrum) (1 point each)
Mass Position (cm)
Output Force (N)
Input Force (N)
Mechanical Advantage
Effort (Circle One):
50 cmXXXXXXXXXXXXX
30 cm More Less
70 cm More Less
4) In order to make the MA “better”, what did you do with the position of the mass?
5) Which side of the lever had to be longer (Input or Output) for the “better” MA?
6) What happened to the MA when the Input side was SHORTER than the Output side?
Third Class Lever (use your finger to hold the lever on the fulcrum) (1 point each)
Input Force Position (cm)
Output Force (N)
Input Force (N)
Mechanical Advantage
Effort (Circle One):
50 cmXXXXXXXXXXXXXX
30 cm More Less
70 cm More Less
7) In order to make the MA “better”, what did you do with the position of the input effort?
8) Which side of the lever had to be longer (Input or Output) for the “better” MA?
9) What happened to the MA when the Input side was SHORTER than the Output side?
30 cm
70 cm
30 cm
50 cm
70 cm
0 cm 100 cm
30 cm
50 cm
70 cm
0 cm 100 cm
Purpose:In this experiment, you will compare the effort required to move an object (as a result of Mechanical Advantage) up ramps of different slopes. You will also calculate the amount of work done by the ramps. What will the results be when you change the steepness and/or height of a ramp?
Work: The result of a force being applied to an object and the measurement of the distance that object has moved. ***Work is measured in joules.
Work (J) = Force x Distance
Mechanical Advantage: When the machine’s output force is greater than the Input force required to operate it. The work becomes easier to accomplish. ***No unit for MA!!!
MA = Output Force/Input Force
Materials
/40If you miss this lab, make sure you attend the make up session during Pride Time
Short Ramp Long Ramp Wood Block Force Meter
Calculator 3 Books Ruler/meter stick Counter edge
Procedures:1. Pile 3 books high.2. Lean the short board against the stack of books so that the board forms a ramp (inclined plane). 3. Measure from the end of the ramp to the bottom corner of the books and then the height from the base
of the books to the top of the books. Record this data in your table.4. Attach the wood block to your force meter, and then drag the block of wood up the ramp. Record the
amount of Input force in your data table.5. Repeat the experiment with the long ramp at the same height. Record this data in the table.6. Calculate the mechanical advantage and work for ramp.7. Repeat steps 2-6 for the experiment using the counter edge to rest your ramps against. The ramps will
both be taller and steeper for these tests.8. Answer the questions that follow.
Predict: (2 points each)1) What will happen to the amount of Input force needed to pull the block as the ramp gets steeper?
2) What will happen to the amount of work we accomplish when the ramp gets longer?3 Book Test: (Have the top of the ramps as close to even with the top of books as you can)
RampLength
of Ramp Base (m)
Height of Ramp
(m)
Output Force (N)(lift straight
up)
Input Force(N)
(Pull up ramp)
MechanicalAdvantage
(Output/Input)
Effort Comparison:(Circle One)
Short More Less
Long More Less
Work accomplished during test: Use the Work equation with the following as your variables: Output Force (N) x Height of Ramp (m) = Work Short Ramp:
Long Ramp:
Edge of Counter test: (Have the top of the ramps as close to even with the top of counter as you can)
RampLength
of Ramp Base (m)
Height of Ramp
(m)
Output Force (N)(lift straight
up)
Input Force(N)
(Pull up ramp)
MechanicalAdvantage
(Output/Input)
Effort Comparison:(Circle One)
Shorter Height but Different SteepnessTaller Height AND Different Steepness
1 point for each item required:
Short More Less
Long More Less
Work accomplished during test: Use the Work equation with the following as your variables: Output Force (N) x Height of Ramp (m) = Work Short Ramp:
Long Ramp:
Post Lab Questions: (2 points each)1. What happened to your mechanical advantage when you used the longer (less steep) ramp?
2. Did the effort increase or decrease when the ramp was steeper? What if it was Taller?
3. What happened to the amount of work you accomplished when the ramp was steeper?
4. If we want to raise an object to a certain height; what would be the best solution? To use a longer ramp or a shorter ramp?
Pulleys are simple machines used to life objects vertically. A pulley consists of a rope wrapped around a wheel. There are three types of pulleys:
Fixed Pulley: Moveable Pulley: Block and Tackle:
Purpose:In this lab you will be determining the actual Mechanical Advantage of all the types of pulley configurations.
/40If you miss this lab, make sure you attend the make up session during Pride Time
Materials:-single pulleys -1 Iron ring-double pulleys -1 500 g mass-1 string -1 20 N Force meter-1 ring stand
Mechanical Advantage Equation: M.A. = Output ForceInput Force
Prediction: (2 pts)Which pulley set-up will produce the highest Mechanical Advantage?
PROCEDURE : 1) Find the Weight (N) of the 500 g mass by hanging it from the force meter: _________ (1 pt)2) Lift (Input) the 500 g mass 5 cm (Output) with the force meter. 3) Record the Output force, Input distance & Input force for each test.4) To find the Input distance: measure the distance the black mark on the string moves. This is the Input distance.
For all amounts in this lab, go ahead and round to the nearest whole number.5) The ratio is how many times greater is the Input distance from the Output distance
Ex: 15 cm Input and 5 cm Output = 3:1 ratio (15 cm is 3 times greater than 5 cm)6) Repeat the experiment for all configurations and record all data in the data table.
Data: (20 pts.)
Pulleys Input Distance
Output Distance
DistanceRatio
In/Out
Output force Input Force Mechanical
Advantage
Single Fixed
(1 Pulley)5 cm
Single Movable(1 Pulley)
5 cm
Block and Tackle
(3 Pulley’s)
5 cm
Double Pulley
(4 Pulley’s)
5 cm
Questions: (2 pts each)
1) What is the relationship between the weight of the mass and the input force on the single pulley system? How does this relate to the mechanical advantage?
2) As you added pulleys to the system, what happened to the amount of effort needed to raise the mass?
3) What is the relationship between the amount of pulleys you had and the ratio of input distance to output distance?
4) How did the number of pulleys used in the system effect the actual mechanical advantage?
5) Write a statement about the relationship between the distances the mass moved relative to the input distance the force meter moved.
1) The force you have to do to a machine is called:
Attempt: ______________________________________________________
Correct: ______________________________________________________
2) A more efficient machine will have a mechanical advantage of…
Attempt: ______________________________________________________
Correct: ______________________________________________________
3) Which of these tools would have a better (higher) Mechanical Advantage?
Attempt: _____________________________________________________
Correct: ______________________________________________________
/24The make up for this quiz, and the answer key, are found on the unit page of the class website
4) What would the mechanical advantage of a machine be that had an output force of 24 N and an input force of 8 N?
Attempt: ______________________________________________________
Correct: ______________________________________________________
5) The force a machine will do as a result of what you did is called:
Attempt: ______________________________________________________
Correct: _______________________________________________________
6) What two things do machines do for us?
Attempt: ______________________________________________________
Correct: _______________________________________________________
7) Which side of the machine needs to be longer for a better mechanical advantage?
Attempt: _______________________________________________________
Correct: ________________________________________________________
8) Which ramp would have a better Mechanical Advantage?
Attempt: ________________________________________________________
Correct: _________________________________________________________
9) If the mechanical advantage of a machine is really low, what will the effort be like?
Attempt: _________________________________________________________
Correct: __________________________________________________________
10) Why would a car be considered to have more power than a bike?
Attempt: ___________________________________________________________
Correct: ____________________________________________________________
11) If the two ramps are the same length, what is wrong with choosing the shorter height ramp to get the job done instead of the taller ramp?
Attempt: ____________________________________________________________
Correct: _____________________________________________________________
12) “What was accomplished?” is another way to ask about what?
Attempt: ____________________________________________________________
Correct: ____________________________________________________________
1. __ Input Force a. Force that is applied to the object2. __ Output Force b. Another word for Leverage3. __ Work c. The pivot for a lever.4. __ Effort d. Force x Distance5. __ Mechanical Advantage e. Force that you apply to the simple
machine6. __ Fulcrum f. Describes the input force
Questions:1. Identify the following terms on the diagram below:
a. Effort armb. Result armc. Input side
d. Input forcee. Output sidef. Output force
2. According to the diagram below, what happens to the amount of effort (Input force) I would need to apply if I moved the fulcrum to where the arrow indicates?
3. Calculate how much work (force x distance) is done on both sides of the lever:
4. Question: which following machine did more work on the object? (BE CAREFUL!!!)
F: 20NOD: 10 cmW: __________
F: 5NID: 40 cmW: _________
/40
5. If I was to make lifting an object with a lever EASIER to do (take less effort) what should I do with the fulcrum?
6. If I wanted to cut thick branches of a tree, which set of trimmers would I want to use? Write next to the correct picture one sentence explaining why:
A B
7. If all the shown masses are equal, which of these levers would have the greatest mechanical advantage?
8. Four levers were built and tested by lifting a large mass which required 4N to move. The effort needed for each is listed here:
a. Lever A = 0.5 Nb. Lever B = 1 Nc. Lever C = 2 Nd. Lever D = 4 N
Which lever had the greatest mechanical advantage?
9. What would the mechanical advantage of a pulley be if the output force was 12 N and an input force of 3 N?
10cm 10cm
20N20N8N 4N
MA =
10. What is the easiest way to increase the MA of a ramp?
11. Why don’t you want to change the height of a ramp when changing the length?
12. On the ramp diagram, if I were to increase the height of the ramp, how would that affect the amount of work I would have to do?
13. Identify the fulcrum point and where the input and output forces are.
14. Which pair of scissors has LESS mechanical advantage? Explainwhy:
15. Question: which following machine did more work on the object? (BE CAREFUL!!!)
10cm 10cm
20N20N8N 4N