In hydroelectric dams, gravitational potential energy is used to produce electrical energy. what is the mass of water that must fall over a dam that is 12 m high in order to produce the same amount of energy in an aa battery (10,800 j)?

What mass of water must fall 12m in order to lose 10,800J of gravitational potential energy ?

Potential energy = (mass) x (gravity) x (height)

10,800J = (mass) x (9.8 m/s²) x (12m)

Mass = (10,800J) / (9.8 m/s² x 12m)

Mass = (10,800 / 9.8 x 12) (Joule-sec²/m²)

(Units:  Joule-sec²/m² = N-m-sec²/m² = (kg-m/s²)-m-sec²/m² = kg )

Mass = 91.8 kg