An electric motor produces a tension of $9000 \ N$ on a reel containing an electric cable at a rate of $2 \ ms^{-1}$. Calculate the power of the electric motor in $kW$.

An athlete of mass $60\, kg$ skips at the rate of $20$ steps per minute through an average height of $25\, cm$. The power developed is ............. $W$.

$A$ $60 \ kg$ man runs up a staircase in $12 \ s$ while a $50 \ kg$ man runs up the same staircase in $11 \ s$. The ratio of the rate of doing their work is:

$A$ body is moving in a straight line by a machine delivering constant power. The distance moved by the body in time $t$ is proportional to:

$A$ pump on the ground floor can pump up water to fill a tank of volume $30 \ m^3$ in $15 \ minutes$. If the tank is $40 \ m$ above the ground and the efficiency of the pump is $30\%$,then the electric power consumed by the pump is ....... $kW$.

The unit of power is