Unit 3: Work, Energy, and Power
Physics C: Mech · Unit 3 · Paper 3

Work, Energy, and Power unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 19 terms and is the same for everyone, so a teacher can assign “Unit 3, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 33 min 30 points0/17 attempted
1

Spring potential energy

2

Reading kinetic energy from a potential curve

3

Power delivered by a constant force

4

Work done by friction

5

Force from potential energy

6

Conservative forces and path independence

7

Potential energy curves

8

Turning points

9

Energy in a spring-mass system

10

Instantaneous power

11

Escape energy

12

Deriving force from U(x)

Short answer 1. Define or explain: Stability from a potential curve

3 pts

Short answer 2. Define or explain: When to use energy rather than forces

3 pts

Short answer 3. Define or explain: Gravitational potential energy in general

3 pts

Short answer 4. Define or explain: Escape velocity

3 pts

Free response

6 pts

A block of mass m is released from rest at the top of a curved, frictionless ramp of height h. At the bottom, it enters a rough horizontal surface with a position-dependent coefficient of kinetic friction μ_k(x) = cx, where c is a positive constant and x is the distance along the rough surface.

Derive an expression for the speed of the block at the bottom of the ramp.

Set up, but do not evaluate, an integral expression to find the total distance D the block travels on the rough surface before coming to rest.

Determine D in terms of m, g, h, and c.