What average horsepower is developed by an $80 \; kg$ man while climbing in $10 \; s$ a flight of stairs that rises $6 \; m$ vertically?

$A$ vehicle of mass $m$ starts from rest and accelerates. If the engine delivers a constant power $P$,then the position $s$ of the vehicle at time $t$ is given by:

$A$ crane of efficiency $80 \%$ is used to lift $8000 \ kg$ of coal from a mine of depth $108 \ m$. If the time taken by the crane to lift the coal is one hour, then the power of the crane (in $kW$) is (Acceleration due to gravity $= 10 \ m \ s^{-2}$)

Assume the aerodynamic drag force on a car is proportional to its speed. If the power output from the engine is doubled,then the maximum speed of the car:

$A$ $10 \text{ H.P.}$ motor pumps out water from a well of depth $20 \text{ m}$ and fills a water tank of volume $22380 \text{ litres}$ at a height of $10 \text{ m}$ from the ground. The running time of the motor to fill the empty water tank is ........... $\text{minutes}$ $(g = 10 \text{ m s}^{-2})$

$A$ car of mass $m$ is accelerating on a level smooth road under the action of a single force $F$. The power delivered to the car is constant and equal to $P$. If the velocity of the car at an instant is $v$,then after travelling how much distance does its velocity become double?