PhysicsLAB: Test Scenario: Advanced Freefall

Refer to the following information for the next ten questions.

During a bouncing ball lab, a student recorded that a 25-gram golf ball took 1.8 seconds between bounces after it was released from the top of a building’s roof. Unfortunately, his partner was not paying attention to how high the ball bounced.

(a) Using the image shown at the left, in which colored marker would the partner have seen the apex?

For example, if another ball had bounced to a height of 3.60 meters your answer would be in Set 3 near the middle of its green rectangle (3.60-2.74 = 0.86 meters).

Each colored band is 10 cm high.

(b) Draw a FBD (free body diagram) showing all of the forces acting on the golf ball when it reached its apex.

(c) If the golf ball was originally released from rest at the very top of the pink strip in Set 6, what was its initial potential energy?

(d) What was the ball’s kinetic energy at the instant just as it struck the pavement at the base of the building (before bouncing)?

(e) How fast was the ball traveling in part (d)?

(f) Based on the height of the experimental golf ball’s apex (h₁) from part (a), what was the ball’s KE as it left the pavement to rise upward?

(g) How fast did the ball leave the ground in part (f)?

Shown below is a series of stop-action pictures showing a golf ball impacting with the ground. The left picture represents when the golf ball was just approaching the bounce (parts d and e) while the last picture represents when the ball had completed the bounce to begin traveling upwards towards the apex (parts f and g). Notice the deformation of the ball during its interaction with the pavement. This deformation supports the following three questions regarding impulse, force, and work.

(h) What impulse did the pavement deliver to the ball during the ball’s first bounce?

(i) If the ball’s impact with the ground lasted for 710 µs (7.10 x 10-4 seconds), what was the average force exerted by the pavement on the ball during the ball’s first bounce?

(j) How much work did the pavement do on the ball during the ball’s first bounce?