Question

A 15 kg ball raised up by 5 m possesses energy called potential energy given by U = mgy, where g = 9.8 m/s^2. What is the value and units of the potential energy, U, for this ball?

Answer 1

U = mgy = (15kg)(9.8m/s^2)(5m) = 735 kg m^2 /s^2 = 735 Nm = 735 J (J = Joules, the SI unit of energy/work)