$A$ train of mass $10^6 \ kg$ is moving at a constant speed of $108 \ km/h$. If the frictional force acting on it is $0.5 \ N$ per $100 \ kg$,then the power of the train is (in $kW$)

An electric pump is used to fill an overhead tank of capacity $9\,m^3$ kept at a height of $10\,m$ above the ground. If the pump takes $5\,minutes$ to fill the tank by consuming $10\,kW$ power,the efficiency of the pump should be : ............... $\%$ (Take $g = 10\,m/s^2$)

$A$ girl of mass $50 \,kg$ is swinging on a cradle. If she moves with a velocity of $2 \,ms^{-1}$ in a direction making an angle of $60^{\circ}$ with the vertical, then the power generated by the gravitational force is $\left(g=9.8 \,ms^{-2}\right)$.

$A$ body is moving unidirectionally under the influence of a constant power source. Its displacement in time $t$ is proportional to :

$A$ pump is used to deliver water at a certain rate from a given pipe. To obtain $n$ times the water in the same time from the same pipe,by what factor should the power of the motor be increased?

$A$ body is initially at rest. It undergoes one-dimensional motion with constant acceleration. The power delivered to it at time $t$ is proportional to