Question

Get a basketball and a tennis ball. It’s ok to borrow one from your neighbors and involve them in your experiment, they will thank you for that later.

Try dropping/releasing them individually onto a floor or other hard surface from the same height you did it in the previous lab. Video recording to measure the height of re-bounce and the time between the bounces to gauge the energy of each bounce. Organize your measurements in a table. Don’t forget to illustrate your results.

Try dropping the two of them together with the tennis ball placed on top of the basketball. It will require some practice. The outcome may surprise you and your assistants. Compare the height of the ball in these three cases: basketball alone, tennis ball alone, and the two together, with tennis ball on top of the basketball. Illustrations and results should be provided for each case.

Can you devise an explanation for these results using impulse and Newton’s third law? (Hint: consider the force between the basketball and the floor as well as that between the tennis ball and the basketball for the case where they are dropped together).

Answer 1

The following table illustrates the height achieved by the ball (basketball and tennis ball when dropped from 3m heigth)

BasketBall
Bounce No.	Height (m)	Final PE/mass	impulse
0	3	29.43
1	2.3	22.563	1.527101213
2	1.7	16.677	1.507674644
3	1.2	11.772	1.476921939
4	0.8	7.848	1.424637158
5	0.5	4.905	1.327561299
6	0.3	2.943	1.129574333
7	0.2	1.962	0.712318579
8	0.15	1.4715	0.424626348

Tennis Ball
Bounce No.	Height (m)	Final PE/mass	impulse
0	3	29.43
1	2.2	21.582	0.220419121
2	1.6	15.696	0.193415018
3	1.1	10.791	0.191442659
4	0.6	5.886	0.242921658
5	0.4	3.924	0.125921324
6	0.2	1.962	0.164103865
7	0.1	0.981	0.116038956
8	0.05	0.4905	0.082051932

Both Together
Bounce No.	Tennis Ball Height (m)	Final PE/mass	impulse	Basketball Height (m)	Final PE/mass	impulse	impulse sum
0	3	29.43		3	29.43
1	4	39.24	-0.237373345	2.2	21.582	1.763352968	1.52598
2	3.5	34.335	0.114431489	1.3	12.753	2.431335974	2.545767
3	2.8	27.468	0.174970808	0.8	7.848	1.741646013	1.916617
4	2	19.62	0.229539689	0.5	4.905	1.327561299	1.557101
5	1.2	11.772	0.282393583	0.3	2.943	1.129574333	1.411968
6	0.6	5.886	0.284236232	0.2	1.962	0.712318579	0.996555
7	0.2	1.962	0.290025189	0.1	0.981	0.928311646	1.218337
8	0.1	0.981	0.116038956	0.05	0.4905	0.65641546	0.772454

as we can see the heigth if balls reduces aftger every collision with surface as there is some loss of energy, but when we drop them together, the tennis ball rises more than initial height. this can be explained by the total impulse.
since the tennis ball gets more impulse from the basket ball, it bouncer more into the air, and as a result we can see that the net impulse on the basketball is sum of impulses due to ground and tennisball, which is the same for the case when baskletball was dropped alone.
this shows that the extra impulse inthe case when both are dropped together is due to the tennis ball and hence tennis ball is able to take extra impulse away from the basket ball as well, causing it to move at lower heights subsequently while the tennis ball gains some enrgy