$A$ body of mass $1 \ kg$ starts from rest and moves with uniform acceleration. In $2 \ s$,its velocity is $10 \ m/s$. The power exerted on the body in $1 \ s$ is (in $W$)

$A$ particle of mass $0.2 \ kg$ is moving in one dimension under a force that delivers a constant power $0.5 \ W$ to the particle. If the initial speed of the particle is zero,the speed (in $m/s$) after $5 \ s$ is:

At any instant of time $t$, the displacement of a particle is given by $x = 2t - 1$ ($SI$ units) under the influence of a force of $5 \,N$. The value of instantaneous power is (in $SI$ units):

Why is electrical power required at all when the elevator is descending? Why should there be a limit on the number of passengers in this case?

An electric pump is used to fill an overhead tank of capacity $9\,m^3$ kept at a height of $10\,m$ above the ground. If the pump takes $5\,minutes$ to fill the tank by consuming $10\,kW$ power,the efficiency of the pump should be : ............... $\%$ (Take $g = 10\,m/s^2$)

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