1. This is a short free-response question. Show your work for each part. Physics students are doing an experiment on impulse and momentum. For the lab, a student drops a ball of mass 2.0 kg from a height of 2.0 m onto a force plate. The ball hits the force plate and rebounds upward. On the rebound, the student records the maximum height of the ball to be 1.7 m. A force sensor on the plate records the magnitude of force in kN (kilonewtons) over a 5.0 ms time interval while the ball is in contact with the force plate. The following graph shows the magnitude of force as a function of time from that data.

https://cdn.flvs.net/assessment_images/educator_apphysics_v23/06_10_pt2_01_flvs.jpg

a.Using their observations, the students accurately claim that the collision between the ball and the force plate is inelastic. Justify their claim using the students' observations. (4 points) b.Using the data given for height, calculate the impulse delivered to the ball by the force plate. (6 points) c. Using the graph, calculate the impulse delivered to the ball according to the data collected from the force plate. Compare your answer with the answer calculated in part b. Does the instrument provide a reliable measurement of the impulse delivered to the ball by the force sensor? Justify your answer. (5 points)

2. This question is a long free-response question. Show your work for each part. Physics students are studying linear and simple harmonic motion. They place two identical blocks on a horizontal, frictionless surface. On the left side of their setup is a horizontal, ideal spring with negligible mass and a spring constant k₁ connected to a vertical wall. They place block A up against the spring, compressing it a distance d₁, while holding it in place. The figure below shows scenario 1 and four stages of the experiment at specific time intervals: t₁ through t₄.

https://cdn.flvs.net/assessment_images/educator_apphysics_v23/06_10_pt2_06_01_flvs.jpg

The following table describes the events that occurred in Scenario 1:

Time	Events
t1	Block A is released. Block B is at rest on the other end of the setup.
t2	The spring is uncompressed a distance of d1. Block A departs the spring.
t3	Block A collides with and sticks to block B.
t4	Blocks A and B move along the surface together.

1. Consider the time interval t₁ to just after t₂. Is the linear momentum of the two-block system increasing, decreasing, or constant? Briefly explain. (3 points)
2. Consider the time interval t₁ through t₂. Does the spring do zero work, positive work, or negative work on the two-block system? Briefly explain. (3 points)
3. Consider the time interval t₂ through t₄. Is the mechanical energy of the two-block system increasing, decreasing, or constant? Briefly explain. (3 points)
4. In scenario 2, the students set up the experiment identical to scenario 1 except the students use a softer spring. For scenario 2, k₂ < k₁ and the spring compresses the same distance as in scenario 1, d₁. Block A still collides with and sticks to block B. The following graph shows the displacement for block A and then block A and block B together as a function of time after through t₄. One line represents scenario 1 (larger spring constant), and the other represents scenario 2 (smaller spring constant).

https://cdn.flvs.net/assessment_images/educator_apphysics_v23/06_10_pt2_06_02_flvs.jpg

Indicate which lines the solid or dotted line curve, represent each scenario. Briefly expalin your reasoing, including a comaprasion of the speed of block once realesed from the spring in each scenraio