Recall and use the equation for the change in gravitational potential energy ΔE_p = mgΔh

Recall and use the equation work done = force × distance moved in the direction of the force, W = Fd

Define power as work done per unit time and also as energy transferred per unit time; recall and use the equations (a) power = work done / time taken, P = W/t (b) power = energy transferred / time taken, P = ΔE/t