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?

Question

options:
As soon as she drops it
As soon as she drops it

At the very top of its bounce
At the very top of its bounce

Just after it hits the ground
Just after it hits the ground

Exactly when it hits the ground

Answer 1

The ball has zero kinetic energy at the very top of its bounce. At this point, the ball is momentarily at rest before it begins to fall back down again. Therefore, the correct option is:

At the very top of its bounce

Answer 2

Which statement best describes the relationship between a baseball’s potential and kinetic energy after it is thrown? (assume the ball travels in a straight line)

options:
Potential energy does not change, and kinetic energy decreases.
Potential energy does not change, and kinetic energy decreases.

Potential energy increases, and kinetic energy does not change.
Potential energy increases, and kinetic energy does not change.

Potential and kinetic energy both decrease.
Potential and kinetic energy both decrease.

Potential energy decreases as kinetic energy increases.
Potential energy decreases as kinetic energy increases.

Answer 3

When a baseball is thrown in a straight line, its kinetic energy is primarily influenced by its speed, while its potential energy is affected by its height above ground level. As the baseball travels away from the thrower, it typically moves horizontally and maintains a relatively constant height (assuming no significant changes in elevation).

1. At the moment it is thrown, the baseball has high kinetic energy and some potential energy based on its height.
2. As it travels horizontally, its height remains approximately the same, meaning its potential energy does not change much, unless it starts to drop or rise significantly (which isn't implied in your description).
3. Therefore, its kinetic energy remains fairly constant until external factors such as air resistance begin to slow it down.

Given these considerations, the statement that best describes the relationship after the ball is thrown is:

Potential energy does not change, and kinetic energy decreases.

This acknowledges that while the potential energy remains relatively constant during horizontal flight, kinetic energy may decrease due to factors like air resistance.