$A$ force of $(2\hat{i} + 3\hat{j} + 4\hat{k})\,N$ acts on a body for $4\,s$ and produces a displacement of $(3\hat{i} + 4\hat{j} + 5\hat{k})\,m$. The power used is :- ............... $W$ (in $.5$)

$A$ force applied by an engine of a train of mass $2.05 \times 10^6 \; kg$ changes its velocity from $5 \; m/s$ to $25 \; m/s$ in $5$ minutes. The power of the engine is ........... $MW$.

The machine gun fires $240$ bullets per minute. If the mass of each bullet is $10 \ g$ and the velocity of the bullets is $600 \ ms^{-1}$,the power (in $kW$) of the gun is

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

$A$ body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time $t$ is proportional to

$A$ man of mass $50 \ kg$ carries an object to a height of $20 \ m$ in a time of $10 \ s$. The power used by the man in this process is $2000 \ W$. Find the mass of the object carried by the man (take $g = 10 \ m/s^2$). (in $kg$)