Unit 4: Linear Momentum
Physics 1 · Unit 4 · Paper 2

Linear Momentum 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 37 terms and is the same for everyone, so a teacher can assign “Unit 4, Paper 2” 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 36 min 33 points0/17 attempted
1

Momentum in a system with external forces

2

System choice

3

Center-of-mass velocity

4

The condition for momentum conservation

5

Perfectly inelastic collision

6

Impulse-momentum theorem

7

Elastic collision

8

Momentum vs kinetic energy conservation

9

K = p²/2m

10

Perfectly inelastic collision speed

11

Why a longer collision time reduces force

12

Why collisions can ignore friction

Short answer 1. Define or explain: Momentum vs kinetic energy

3 pts

Short answer 2. Define or explain: Explosions

3 pts

Short answer 3. Define or explain: Impulse from a graph

3 pts

Short answer 4. Define or explain: Reading a force-time graph

3 pts

Free response

9 pts

On a horizontal frictionless track, cart A (mass 0.50 kg) moves to the right at 4.0 m/s and collides with cart B (mass 1.5 kg), which is initially at rest. After the collision, cart A moves to the left at 1.0 m/s.

Calculate the velocity of cart B after the collision, including direction.

Determine whether the collision is elastic, supporting your answer with a calculation.

The carts are in contact for 0.050 s. Calculate the magnitude and direction of the average force exerted on cart A by cart B.

Calculate the velocity of the center of mass of the two-cart system before and after the collision, and explain what your result demonstrates.

A student claims the data must be wrong because cart A “bounced backward off a lighter object.” Evaluate this claim.