# 1.6(d). Power

The rate of doing work is called power.

A powerful engine in a car can take you up a road to the top of a mountain more quickly than a less-powerful engine. Both engines can do the work, given enough time, but the powerful engine can do the work more quickly. In the same way, a powerful electric motor on a cooling fan will move the air in the room more quickly; and the ‘powerfully built’ athlete will, by transferring more kinetic energy to it as it is launched, throw the javelin further.

If work W is done in time t, then Power

$P=\frac{W}{t}$

S.I unit is watt (W).

$1&space;W=&space;\frac{1&space;J}{1s}$

Horse Power is another unit of power, largely used in mechanical engineering.

$1 H.P=746 W$