Which of the following must be known in order to determine the power output of an automobile?

$A$ 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 $.............$

Show that the rate of change of kinetic energy is a power.

$A$ $60 \ kg$ man runs up a staircase in $12 \ s$ while a $50 \ kg$ man runs up the same staircase in $11 \ s$. The ratio of the rate of doing their work is:

$A$ weight lifter lifts $300 \ kg$ from the ground to a height of $2 \ m$ in $3 \ s$. The average power generated by him is $... \ W$.

$A$ body of mass $2 \,kg$ starts from rest and moves with uniform acceleration. It acquires a velocity $20 \,ms^{-1}$ in $4 \,s$. The power exerted on the body in $2 \,s$ in watts is