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

$A$ constant force $F$ acts on a body of mass $m$ initially at rest. Which of the following graphs correctly represents the variation of the power $P$ developed with time $t$?

$A$ car of mass $1200 \,kg$ (together with the driver) is moving with a constant acceleration of $2 \,m/s^2$. How much power does the engine generate at the instant when the speed reaches $20 \,m/s$ (in $\,W$)? (Assume that the coefficient of friction between the car and the road is $0.5$ and $g = 10 \,m/s^2$).

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

$A$ force $\vec{F} = (4 \hat{i} + \hat{j} - 2 \hat{k}) \text{ N}$ acting on a body maintains its velocity at $\vec{v} = (2 \hat{i} + 2 \hat{j} + 3 \hat{k}) \text{ m s}^{-1}$. The power exerted is $..... \text{ W}$.

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