An electric motor produces a tension of $9000 \ N$ on a reel containing an electric cable at a rate of $2 \ ms^{-1}$. Calculate the power of the electric motor in $kW$.

The average work done by a human heart while it beats once is $0.5 \, J$. Calculate the power used by the heart if it beats $72$ times in a minute.

$A$ body is moving along a straight line under the influence of a constant power source. If the relation between the displacement $(s)$ of the body and time $(t)$ is $s \propto t^x$, then $x=$

$A$ car of mass $m$ has an engine which can deliver power $P$. The minimum time in which the car can be accelerated from rest to a speed $v$ is .............

$A$ body of mass '$M$' is moving with a uniform speed of '$v$' on a frictionless horizontal surface under the influence of two forces $F_1$ and $F_2$ as shown in the figure. The net power of the system is

$A$ pump draws water from a tank which is $2.5\; m$ below the outlet and discharges it through a hose. The cross-sectional area of the hose is $10\; cm^{2}$,and the water leaves the end of the hose at a speed of $5\; m/s$. What is the power at which the pump is working (in $; W$)? (Assume $g = 10\; m/s^{2}$)