$A$ car of mass $2000 \ kg$ is accelerating from rest. If its engine is supplying a constant power of $10 \ kW$,then the velocity of the car at a time of $10 \ s$ is: (in $m \ s^{-1}$)

$A$ body of mass $2 \ kg$ is initially at rest. It starts moving unidirectionally under the influence of a source of constant power $P$. Its displacement in $4 \ s$ is $\frac{1}{3} \alpha^2 \sqrt{P} \ m$. The value of $\alpha$ will be $.............$

$A$ lift raises $50$ passengers, each having an average weight of $600 \,N$, to a height of $100 \,m$ at a constant speed in time $t$. If the average power of $15 \,kW$ is required by the lift, then the value of $t$ in seconds is:

$A$ 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.

$A$ force of $(60 \hat{i} + 15 \hat{j} - 3 \hat{k}) \text{ N}$ produces a velocity of $(2 \hat{i} - 4 \hat{j} + 5 \hat{k}) \text{ m/s}$ in a particle. The value of power at that time will be: (in $\text{ W}$)

Calculate the power of a crane in watts,which lifts a mass of $100 \, kg$ to a height of $10 \, m$ in $20 \, s$. (in $, W$)