At a place where the acceleration due to gravity is $10\,m/s^2$,a force of $5\,kg-wt$ acts on a body of mass $10\,kg$ initially at rest. The velocity of the body after $4\,s$ is .......... $m/s$.

$A$ body under the action of a force $\vec{F} = 6\hat{i} - 8\hat{j} \text{ N}$ acquires an acceleration of $5 \text{ m s}^{-2}$. The mass of the body is ........ $\text{kg}$.

The figure represents the momentum-time $(p-t)$ curve for a particle moving along an axis under the influence of a force. Identify the regions on the graph where the magnitude of the force is maximum and minimum,respectively.

$A$ cricket ball of mass $50 \ g$ having velocity $50 \ cm \ s^{-1}$ is stopped in $0.5 \ s$. The force applied to stop the ball is (in $N$)

$A$ body of mass $0.05 \ kg$ is observed to fall with an acceleration of $9.5 \ ms^{-2}$. The opposing force of air on the body is $(g = 9.8 \ ms^{-2})$.

$A$ constant retarding force of $50\; N$ is applied to a body of mass $20\; kg$ moving initially with a speed of $15\; m/s$. How long (in $sec$) does the body take to stop?