AP Physics C Mechanics 4.2 Impulse and Momentum

[Maximum number: 1]

Scientists have created a new type of lightweight foam and are performing experiments to investigate the properties of the foam. The mass of Cart A is 1000 kg and the mass of Cart B is 2000 kg. A piece of foam with negligible mass is attached to the front of Cart A, as shown. Cart A moves with a constant speed toward Cart B, which is initially at rest. At time $t=0 \mathrm{~s}$ , the foam connected to Cart A makes contact with Cart B. The foam remains in contact with Cart B for 0.5 s, after which the carts separate and both carts move with constant velocities.

Figure for Question AP Physics C: Mechanics 4.2 B Describe the Relationship Between the Impulse Exerted on an Object or System and the Change in Momentum of the Questions question 1 — AP Physics C: Mechanics

What is the relationship between the magnitude of the average net force $F_{1}$ exerted on Cart B for the collision with the foam and the magnitude of the average net force $F_{2}$ exerted on Cart B for the collision without the foam? $F_{1}>F_{2}$ $F_{1}<F_{2}$ $F_{1}=F_{2}$
Justify your answer.

For selecting $F_{1}<F_{2}$ with an attempt at a relevant justification

1 point

For indicating that the impulse or change in momentum of each cart in both collisions is the
same

1 point

For indicating that decreasing the time of collision means the average force must be greater

1 point

Example Solution
Since the initial and final velocities are the same for both collisions, $\Delta p$ is the same for both collisions;
as a result, the impulse is the same for both collisions. So, if $\Delta t$ is smaller, $F_{\text {avg }}$ is larger.

Total for part (c)

for question 1

15 points

AP Physics C: Mechanics 4.2 B Describe the Relationship Between the Impulse Exerted on an Object or System and the Change in Momentum of the Questions question 1