Rita throws a ball straight up into the air and catches it at the same position from which she threw it. The ball has 18 J of mechanical energy when it leaves her hand. If no energy is lost due to friction, which statements about the energy of the ball are true? Choose four correct answers.

With no friction, the ball’s total mechanical energy remains constant at 18 J, so B is true. As the ball rises, kinetic energy changes into potential energy; as it falls, kinetic energy increases while potential energy decreases, making C and E true. At the top, the ball momentarily has zero kinetic energy, so its potential energy is the full 18 J, making D true. It has the same kinetic energy when thrown and caught because it returns to the same height, so F is false.

AI-written and checked against the verified answer.