Question

2016 P PHYSICS 1 FREE-RESPONSE QUESTIONS 2. (12 points, suggested time 25 minutes) new kind of toy ball is advertised to "bounce perfectly elastically" off hard surfaces. A student suspects, however, that no collision can be perfectly elastic. The student hypothesizes that the collisions are very close to being perfectly elastic for low-speed collisions but that they deviate more and more from being perfectly elastic as the collision speed increases. (a) Design an experiment to test the student's hypothesis about collisions of the ball with a hard surface The student has equipment that would usually be found in a school physics laboratory. i. What quantities would be measured? ii. What equipment would be used for the measurements, and how would that equipment be used? ii. Describe the procedure to be used to test the student's hypothesis. Give enough detail so that another student could replicate the experiment (b) Describe how you would represent the data in a graph or table. Explain how that representation would be used to determine whether the data are consistent with the student's hypothesis. (c) A student carries out the experiment and analysis described in parts (a) and (b). The student immediately concludes that something went wrong in the experiment because the graph or table shows ! chavior that is elastic for low-speed collisions but appears to violate a basic physics principle for high-speed collisions i. Give an example of a graph or table that indicates nearly elastic behavior for low-speed collisions but appears to violate a basic physics principle for high-speed collisions State one physics principle that appears to be violated in the graph or table given in part (c)i. Several physies principles might appear to be violated, but you only need to identify onc. ii. Briefly explain what aspect of the graph or table indicates that the physics principle is violatd and why 2016 The College Board. Visit the College Board on the web www colleget arderg. GO ON TO THE NEXT PAGE.

Answer 1

(2)

(i)

Quantities to be measured are

(1) speed of the ball and hard surface before collision.

(2) speed of the ball and hard surface after collision

(3) mass of the ball

(4) momentum of the system before collision and after collision.

(5) Total energy of ball before collision and after collision.

(ii)

Equipment used are movement sensors which can detect velocity of the ball and calculator, ball.

(iii)

Throw the ball on the hard surface

Record the velocity of the ball just before the collision and just after the collision.

Repeat the above steps 5 times and record the data

(b)

Total momentum should be conserved. Momentum of the system just before collision should be equal to the total momentum after collision.

In the graph total momentum should be some constant for each step.

(c)

(ii) It will be the violation of conservation of momentum.

Answer 2

the speed of the ball is 4