A student bounces a tennis ball, she drops the ball and then it bounces bal up to her when does the ball have zero kinetic energy
The ball will have zero kinetic energy at the highest point of its bounce, just before it starts to descend back down. At this point, it momentarily comes to a stop before changing direction, so its kinetic energy is zero.
The ball will have zero kinetic energy at two points in this scenario: when it reaches its highest point during the bounce and when it is released from the student's hand before it starts to fall. Let's break it down step by step:
1. The student holds the tennis ball in her hand, ready to drop it. At this point, the ball is at rest, so it has zero kinetic energy.
2. The student releases the ball from her hand, and it starts to fall due to gravity. As the ball falls, its potential energy decreases and its kinetic energy increases.
3. As the ball reaches the lowest point of its fall, right before it hits the ground, its potential energy is at its minimum while its kinetic energy is at its maximum. This is because all of the potential energy has been converted into kinetic energy.
4. The ball hits the ground and bounces back up. As it rises, its kinetic energy starts to decrease, and its potential energy starts to increase.
5. At the highest point of the bounce, the ball momentarily comes to a stop before changing direction and falling back down. At this point, the ball has reached its maximum height, so its velocity is zero. Therefore, its kinetic energy is zero too, while its potential energy is at its maximum.
6. The ball descends back down towards the student. Its potential energy decreases, and its kinetic energy increases again as it accelerates due to gravity.
7. The ball reaches the student's hand again, and the cycle repeats as she drops it once more.
So, in conclusion, the tennis ball has zero kinetic energy when it reaches the highest point of its bounce and when it is released from the student's hand.
To answer this question, we need to understand what kinetic energy is. Kinetic energy is the energy possessed by an object due to its motion. It depends on the mass and velocity of the object.
In the given scenario, when the student drops the tennis ball, it starts to fall towards the ground under the influence of gravity. As it falls, its velocity increases, and therefore its kinetic energy also increases.
The ball reaches its maximum velocity and kinetic energy just before it hits the ground. At this point, all of its potential energy (energy due to its position above the ground) has been converted into kinetic energy. This is known as the point of maximum kinetic energy.
After hitting the ground, the ball bounces back up. As it rises, its velocity decreases until it momentarily comes to a stop at the highest point of its bounce. At this point, the ball has reached its maximum height and is momentarily at rest. Therefore, as the ball reaches its highest point, it has zero velocity and, consequently, zero kinetic energy.
It's important to note that at any other moment during the ball's motion, such as during the initial drop or during its upward journey after bouncing, the ball would have non-zero kinetic energy. The only moment when the ball has zero kinetic energy is the instant when it reaches its highest point during the bounce.