$A$ pump is used to lift $7200 \ kg$ of water per hour from a depth of $100 \ m$. Calculate the power of the pump in $kW$. Assume its efficiency is $50\%$.

$A$ body is moving along a straight line under the influence of a constant power source. If the relation between the displacement $(s)$ of the body and time $(t)$ is $s \propto t^x$, then $x=$

When a constant force is applied to a body moving with constant acceleration,power does not remain constant. For power to be constant,the force has to vary with speed as follows:

$A$ block of mass $50 \,kg$ is pulled with a constant speed of $4 \,ms^{-1}$ across a horizontal floor by an applied force of $500 \,N$ directed $30^{\circ}$ above the horizontal. The rate at which the force does work on the block in watt is

$A$ $60\; HP$ electric motor lifts an elevator having a maximum total load capacity of $2000\; kg$. If the frictional force on the elevator is $4000\; N$,the speed of the elevator at full load is close to .............. $m/s$.
$(1\; HP = 746\; W, g = 10\; ms^{-2})$

The power of a water pump is $4 \,kW$. If $g = 10 \,m/s^2$,the amount of water it can raise in $1 \,minute$ to a height of $20 \,m$ is ........... $litres$.