1. The problem statement, all variables and given/known data A man pumps water at a rate of 20 liters per minute to a height of 10 meters. How much work does he do in an hour? Friction is to be neglected. A liter of water is taken to weigh 1 kilogram. 2. Relevant equations 3. The attempt at a solution If 1 liter=1 Kilogram then 20 liters = 20 kg Work is a kind of energy conversion. The work done per unit of time is P= ΔE/ ΔT = (20)(9.8)(10)/(60minutes) = 32.67J/minute Is this correct? I'm unsure about the conversions?