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 ............. $W$.

From a waterfall,water is pouring down at the rate of $100 \,kg/s$ on the blades of a turbine. If the height of the fall is $100 \,m$,the power delivered to the turbine is approximately equal to .......... $kW$.

$A$ car of mass $2000 \ kg$ is lifted by a crane through a distance of $30 \ m$ in $1 \ minute$. $A$ second crane does the same in $2 \ minutes$. The power supplied by each crane is respectively:

The power of a pump,which can pump $200 \ kg$ of water to a height of $50 \ m$ in $10 \ s$,will be:

The average power generated by a $90 \ kg$ mountain climber who climbs a summit of height $600 \ m$ in $90 \ minutes$ is (Acceleration due to gravity $= 10 \ ms^{-2}$). (in $W$)

$A$ 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?