Assume it starts and ends at rest.
you forgot to account for gravity its energy = m x g x h
Energy = m x h = 48 kg x 40 m = 1920 Joules Power = Energy per unit time = 1920J / 5 sec = 384 Watts This is the *average power*; that's all that can be calculated from the information given (no data about force or acceleration rates)
