A 500 g stone is thrown up

with a velocity of 15ms.

Find its

(i) P. E. at its maximum height

(ii) K. E. when it hits the ground

Assuming no loss in energy when going up or down (i. e. neglect air resistance), the energies are the same at the maximum height as well as the ground.

(II) the initial energy is all kinetic (so is the final energy when it hits the ground), so

KE = (mv^2) / 2 = 0.5kg * ((15^2) m^2/s^2) / 2 = 56.25 J.

(i) PE at top = KE at bottom = 56.25 J.