Unit 4: Linear Momentum
Physics C: Mech · Unit 4 · Paper 1

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 16 terms and is the same for everyone, so a teacher can assign “Unit 4, Paper 1” 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 37 min 34 points0/17 attempted
1

Elastic collision in one dimension

2

Conservation of momentum

3

Momentum and impulse as integrals

4

Elastic collision special cases

5

Rocket equation qualitatively

6

Impulse-momentum in two dimensions

7

Perfectly inelastic collision

8

Center of mass by integration

9

Momentum conservation with a pivot

10

Kinetic energy lost in a collision

11

Deciding whether momentum is conserved

12

Motion of the center of mass

Short answer 1. Define or explain: Ballistic pendulum sequence

3 pts

Short answer 2. Define or explain: Center of mass

3 pts

Short answer 3. Define or explain: Variable-mass systems

3 pts

Short answer 4. Define or explain: Two-dimensional collisions

3 pts

Free response

10 pts

A 2.0 kg cart rests on a frictionless horizontal track. Starting at t = 0 a horizontal force F(t) = (6 N/s²)t² acts on it for 2.0 s.

Starting from Newton’s second law, show that the impulse delivered equals ∫F dt, and calculate that impulse.

Determine the cart’s speed at t = 2.0 s.

The cart then collides with and sticks to a stationary 6.0 kg cart. Determine the velocity of the pair after the collision.

Determine the kinetic energy lost in the collision and explain where that energy goes.

Determine the impulse delivered to the 6.0 kg cart during the collision and state how it compares with the impulse delivered to the 2.0 kg cart.

State the velocity of the center of mass of the two carts immediately before and immediately after the collision.