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

$A$ cylindrical well of radius $2.5 \ m$ has water up to a height of $14 \ m$ from the bottom. If the water level is at a depth of $6 \ m$ from the top of the well,then the time taken (in minutes) to empty the well using a motor of $10 \ HP$ is approximately,(Take $g = 10 \ m/s^2$)

$A$ body of mass $1 \text{ kg}$ begins to move under the action of a time-dependent force $\vec{F} = (t\hat{i} + 3t^2\hat{j}) \text{ N}$, where $\hat{i}$ and $\hat{j}$ are the unit vectors along $x$ and $y$ axes. The power developed by the above force at time $t = 2 \text{ s}$ will be (in watt):

$A$ body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time $t$ is proportional to :

$A$ particle is moving unidirectionally on a horizontal plane under the action of a constant power supplying energy source. The displacement $(s)$ - time $(t)$ graph that describes the motion of the particle is (graphs are drawn schematically and are not to scale)

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