Work, energy and power
Work is done (or energy is transferred) when an object is moved against a force, and is defined as:
In the Imperial fps system expression 1.5 gives a unit of ft lb f. For metric systems the unit is cm kg f. The SI unit of work is the joule, where 1 J = 1 N m (= 1 m2 kg s−2). Table 1.8 compares these, and other, units of work.
Power is the rate at which work is performed:
