A student bounces a tennis ball. She drops the ball, and then it bounces back up to her. When does the ball have zero kinetic energy?(1 point) Responses Just after it hits the ground Just after it hits the ground At the very top of its bounce At the very top of its bounce Exactly when it hits the ground Exactly when it hits the ground As soon as she drops it As soon as she drops it
The correct answer is "Just after it hits the ground."
The ball has zero kinetic energy when it is at the very top of its bounce.
To determine when the ball has zero kinetic energy, we need to understand the concept of kinetic energy. Kinetic energy is the energy an object possesses due to its motion. It is defined as one-half times the mass of an object multiplied by the square of its velocity.
In the given scenario, the ball is dropped and bounces back up. Initially, when the ball is dropped, it has gravitational potential energy due to its position above the ground. As it falls, this potential energy is converted into kinetic energy. At the moment it hits the ground, all the potential energy is converted to kinetic energy, resulting in maximum kinetic energy. As it bounces back up, the kinetic energy gradually decreases and is eventually reduced to zero.
Therefore, the ball has zero kinetic energy at the very top of its bounce. This is because its velocity is momentarily zero, reaching the highest point of its trajectory. It starts to descend again due to the force of gravity, and as it gains speed, its kinetic energy increases.
Hence, the correct answer is: At the very top of its bounce.