Question

when a ball is thrown up into the air, and it reaches its highest point, wheat energy does it have??

Answer 1

If we were to throw the ball vertically up, then on reaching the highest point it would stop momentarily before coming back down.

Hence at the highest point for this particular trajectory, the energy is purely potential energy.

But, if the trajectory is not vertical, suppose it is thrown at some angle with the ground ( not 90 degrees), then at the highest point it would still have a velocity (purely horizontal as the vertical component of velocity at the highest point becomes zero).

For this situation, the energy at the highest point would be potential energy + kinetic energy.