$A$ 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?

An object of mass $2 \, kg$ is placed at rest in a frame $S_1$ moving with velocity $10 \hat{i} + 5 \hat{j} \, m/s$ and having acceleration $5 \hat{i} + 10 \hat{j} \, m/s^2$. The object is also seen by an observer standing in a frame $S_2$ moving with velocity $5 \hat{i} + 10 \hat{j} \, m/s$. Calculate the net force acting on the object with respect to the $S_1$ frame.

$A$ force separately produces accelerations of $18 \ m/s^2$,$9 \ m/s^2$,and $6 \ m/s^2$ in three bodies of masses $P$,$Q$,and $R$ respectively. If the same force is applied on a body of mass $P+Q+R$,then the acceleration of that body is: (in $m/s^2$)

An object of mass $2 \, kg$ at rest at the origin starts moving under the action of a force $\vec{F} = (3t^2 \hat{i} + 4 \hat{j}) \, N$. The velocity of the object at $t = 2 \, s$ will be ............. $m/s$.

$A$ particle of mass $m$ at rest is acted upon by a force $P$ for a time $t$. Its kinetic energy after an interval $t$ is

$A$ constant force acting on a body of mass $3.0 \, kg$ changes its speed from $2.0 \, m/s$ to $3.5 \, m/s$ in $25 \, s$. The direction of the motion of the body remains unchanged. What is the magnitude and direction of the force?