AP PhysicsMonday 13.12.09 Standards: C4a,b Calculate Power required to maintain a constant acceleration of an object.Objective: S WBAT calculate the power use of systems utilizing energy

Agenda1. Warm Up2. Review HW Turn in HW Packets E#3

to E#73. Power Notes4. Power Practice

Warm UpThe roller coaster desperado has a vertical drop of 68.6 m. At the bottom of the drop the speed of the 50 kgvroller coaster carts is 35.6 m/s. How much energy is lost due to friction?

HomeworkE#8

Work & Energy Test Thursday

AP PhysicsTuesday 13.12.10Standards: C1b2&3 Objective: SWBAT extend their understand of energy by applying those principles to more complex situations.

Agenda1. Warm Up2. Review HW3. Extension Assignment E#9

Warm UpFreebie: What kind of graph did you create for Friday’s lab?

HomeworkE#9 ReviewLab Due Tomorrow

AP PhysicsWednesday 13.12.11Standards: C2b4&5 conservative forces & potential energy from gravity and springs Objective: SWBAT review for their test.

Agenda1. Warm Up2. Collect Energy Lab3. Test Review

HomeworkStudy For Test

Warm UpA compressed spring has 16 J of of potential energy. What is the maximum speed it can impart to a 2 kg object?

AP PhysicsThursday 13.12.05Standards: C3ab: Conservation of EnergyObjective: SWBAT score 4 or higher on their energy exam.

Agenda1. Warm Up2. Take Energy Exam

HomeworkFinalize Lab

Warm UpStudy for test 5 min. Write down one thing you learned while preparing.

AP PhysicsFriday 13.12.06Standards: Cab Conservation of Energy1b3 Objective: SWBAT learn from their mistakes on the exam.

Agenda1. Warm Up2. Review Test3. Correct Mistakes

HomeworkFinal Review will be online by Saturday. Finish Correcting Test Mistakes.

Warm UpFind the change in kinetic energy if a 5kg object is held 10 m in the air then dropped onto a table 2 meters in the air.

AP Lab Write Up RubricSection 4 3 2 1Question/Hypothesis The central question the lab is

asking is stated along with a plausible hypothesis

The central question is stated and something resembling a hypothesis is stated

Only the central question is stated

The section is missing or contains the wrong central question.

Materials/Procedures The procedures are written step by step in complete sentences and the materials are clearly listed.

The procedures and materials are listed but unorganized. The procedure does not explain the lab

Either the procedures or the materials are incomplete.

Only procedures are present, or only materials are present.

Data Collection The lab contains a table and a graph that represents the data accurately and is labeled correctly with the equation of the line written.

The lab contains a table and a graph but it may be missing some labels and the graph may not be done correctly.

The lab is missing a graph completely.

The data is incomplete.

Calculations Students have all calculations completed, with work shown, and they are correct.

Students have all calculations completed and at least half are done correctly and all work is shown.

Students do not have all calculations completed, and little work is shown.

Calculations section is mostly or entirely missing.

Analysis The student gives evidence from their lab data why their hypothesis is true, false, or inconclusive. The discuss the relationships between the variables that were graphed and if linear they write down the equation of the line.

The students gives evidence from their lab data and attempts to prove that the hypothesis is false, true or inconclusive, but the data is misapplied and doesn’t support their claim. For linear graphs, no equation is given.

This section discusses whether the hypothesis is true, inconclusive, or false but no data is used to support the hypothesis and any reference to the graph or the data is too general to be helpful.

This section is omitted or the student may mention the hypothesis and its validity, but doesn’t explain or the explanation is not plausible

Conclusion The conclusion includes a summary of your lab results, (which will include numbers or equations), gives %error and discusses sources of error. It also gives a suggestion about how to improve the lab.

The conclusion includes a summary of your lab results. It includes data. % error is given. Either and least 1 source of error discussed or a suggestion is given to improve the lab.

The conclusion includes a summary and either % error, or mentions types of error, or mentions improving the experiment.

The conclusion is omitted or only includes a brief summary.

Conservation of Energy LabObjective: Students will use the concept of conservation of energy to verify the mass of the marble by rolling it down ramps of different heights.

Theory: Conservation of Energy: As Potential Energy decreases, kinetic energy increases, so by the time the ball reaches the flat surface all the potential energy should have been converted into kinetic energy.

How will you know you’re successful?-The slope of your ___ vs ____ graph will equal (½)m. Using that slope you will be able to calculate mass. -You can compare your experimental mass value with the found found using a spring scale and/or a triple beam balance using a percent error calculation.

Lab Write Up, Using Standard Lab Write Up Rubric Due Wednesday

Power #E81. (1) The most powerful ice breaker in the world was built in the former

Soviet Union. The ship is almost 150 m long, and its nuclear engine generates 56MW of power. How much work can this engine do in 1.0 h?

2. (2) Reginald Esuke from Cameroon ran over 3 km down a mountain slope in just 62.25 min. How much work was done if the power developed during Esuke’s descent was 585.0W.

3. (4) The first practical car to use a gasoline engine was built in London in 1826. the power generated by the engine was just 2984 W. How long would this engine have to run to produce 3.60x104 J of work?

4. (5) Dennis Joyce of the United States threw a boomerang and caught it at the same location 3.0 min later. Suppose Joyce decided to work out while waiting for the boomerang to return. If he expended 54 kJ of work, what was his average power output during the workout?

5. (6) In 1984, Don Cain threw a flying disk that stayed aloft for 16.7 s. Suppose Cain ran up a staircase during this time, reaching a height of 18.4 m. If his mass was 72.0 kg, how much power was needed for Cain’s ascent?

Power

Most things require a continuous flow of energy in order to run. They require power.

Average Power = Work/time or Force*average velocity

P=W/t = Fv

The Units of Power are Watts or J/s.

We see Power mostly in reference to light bulbs and things that we plug in. The electricity companies measure our electricity consumption using kW*hr to bill us.

Power Guided Practice

Martinus Kuiper of the Netherlands ice skated for 24 h with an average speed of 6.3 m/s. Suppose Kuiper’s mass was 65 kg. If Kuiper provided 520 W of power to accelerate for 2.5 s, how much work did he do?