$A$ man $M_1$ of mass $80 \ kg$ runs up the stairs with a box in $15 \ s$. Another man $M_2$ of the same mass $80 \ kg$ runs up the same stairs with the same box in $20 \ s$. Find the ratio of the power generated by them.

Power of a water pump is $2 \, kW$. If $g = 10 \, m/s^2$,the amount of water it can raise in one minute to a height of $10 \, m$ is .............. $liter$.

$A$ 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 $kW$)

$A$ force applied by an engine of a train of mass $2.05 \times 10^6 \; kg$ changes its velocity from $5 \; m/s$ to $25 \; m/s$ in $5$ minutes. The power of the engine is ........... $MW$.

An elevator can carry a maximum load of $1800 \; kg$ (elevator $+$ passengers) and is moving up with a constant speed of $2 \; m s^{-1}$. The frictional force opposing the motion is $4000 \; N$. Determine the minimum power delivered by the motor to the elevator in watts as well as in horsepower.

Two men have a weight ratio of $5 : 3$. If the ratio of the time taken by them to climb stairs is $11 : 9$,find the ratio of their power.