Physics - W.E.P. Question with Solution | TestHub

Since the surface is smooth and the force $F$ is constant, the acceleration of the block is $a=\frac{F}{m}$. The block starts from rest, so its velocity at time $t$ is $v=at=\frac{F}{m}t$. The instantaneous power delivered by the force is $P=\vec{F}\cdot \vec{v}$. Since the force and velocity are in the same direction, $P=Fv=F\left(\frac{F}{m}t\right)=\frac{F^{2}t}{m}$.