A tennis ball of mass mt is held just above a basketball of mass mb, as shown in
ID: 2205881 • Letter: A
Question
A tennis ball of mass mt is held just above a basketball of mass mb, as shown in the figure below. With their centers vertically aligned, both are released from rest at the same moment, so that the bottom of the basketball falls freely through a height h and strikes the floor. Assume an elastic collision with the ground instantaneously reverses the velocity of the basketball while the tennis ball is still moving down because the balls have separated a bit while falling.
(a) The two balls meet in an elastic collision. To what height does the tennis ball rebound? (Use any variable or symbol stated above along with the following as necessary: g.)
(b) How do you account for the height in (a) being larger than h? Does that seem like a violation of conservation of energy?
Explanation / Answer
The total energy of the system (basketball + tennis ball) is conserved, but it does not mean that the energy of the tennis ball is conserved. Hence during impact between basketball and tennis ball, momentum is transferred, and hence the tennis ball gains kinetic energy that allows it to reach a higher height and higher gravitational potential energy.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.