Awindmill is used to raise water from a well. the depth of the well is 5.0 m. the windmill raises 204 kg of water every day. what is the average useful power extracted from the wind? a. 12 mw b. 120 mw c. 690 mw d. 1700 mw

The work done in raising 204 kg through a distance of 5 m is

       W = (mass) x (gravity) x (height) =

               (204 kg) x (9.8 m/s²) x (5 m) =

                               9,996  kg-m²/s²  =  9,996 joules

Power = (work) / (time) .  That's 9,996 joules per day.  But we always like to
describe power in (joules per second), and there's even a special unit for that . . .
1 joule per second is called "1 watt".

           (9,996 joules/day) x (1 day / 86,400 seconds) =

                    (9,996 / 86,400) joules/second  =  0.1158 watt (rounded)

                                                                   or    115.8 milliwatts

                                                                   or    120 milliwatts (very rounded)

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.