(a)[2]
Explain the meaning of gravitational potential energy and kinetic energy.
(b)
A ball with mass $400\,\text{g}$ is projected with an initial velocity of $30.0\,\text{m s}^{-1}$ at an angle of $45.0^\circ$ above the horizontal, as shown in Fig. 4.1. Air resistance is ignored. The ball reaches its greatest height $H$ after $2.16\,\text{s}$.
(b(i).1)[3]
Calculate the initial kinetic energy of the ball.
(b(i).2)[2]
Calculate the maximum height $H$ reached by the ball.
(b(i).3)[2]
Calculate the gravitational potential energy of the ball at height $H$.
(b(ii).1)[1]
Determine the kinetic energy of the ball at its maximum height.
(b(ii).2)[1]
Explain why the kinetic energy of the ball is not zero at maximum height.