Legend

 W = work F = force d = distance KE = kinetic energy PE = potential energy v = velocity a = acceleration t = time P = power

Power

Power is the rate of doing work.  It is the amount of work done per unit of time.
 Power = W/t The unit for power is Watts (W).  1 W = 1 J/s W = work done t = time

An engine that will do the same amount of work as another in half the time is twice as powerful.  A person in good physical condition can deliver work at a fairly continuous rate of roughly 75 W.  Working at a steady pace, the human body develops power in proportion to the amount of oxygen it consumes.   (Physics kicks in with biology!)

Power Equivalencies

 Quantity Equivalent 1 joule per second 1 W 1 foot-pound per second 1.356 W 1 kilocalorie per hour 1.16 W 1 kilowatt-hour per day 41.7 W 1 kilocalorie per minute 69.77 W 1 horsepower 745.7 W 1 kilowatt 1000 W 1 gallon of gasoline per hour 39 kW 1 gallon of oil per minute 2.5 MW 1 million barrels of oil per day 73 GW
 Mechanical Energy Power