An electric generator coupled to a waterfall produces an average electric power output of 5 kW. The power is used to charge a storage battery. Heat transfer from the battery occurs at a constant rate of 1 kW.

(a) Determine the total amount of energy stored in the battery, (in [kJ]) in 10 hours of operation.

(b) If the water fl ow rate is 200 kg/s and conversion of kinetic energy to electric energy has an effi ciency of 50%, what is the average velocity (in m/s) of the water? Where does the rest of the energy go?