$A$ $10 \,g$ bullet moving at $200 \,m/s$ stops after penetrating $5 \,cm$ of a wooden plank. The average force exerted on the bullet will be .......... $N$.

For the given system,find the tension $T_2$ in the upper string.

Can the work done by a frictional force be positive or negative?

$A$ spring-block system is placed on a rough horizontal floor. The block is pulled towards the right to give the spring some elongation and then released.

When the bomb $Q$ explodes,the trolley of mass $200 \, kg$ travels a distance of $36 \, m$ before coming to rest. What distance will the trolley of mass $300 \, kg$ travel before coming to rest (in $, m$)?

An ideal spring is connected between two blocks of masses $M$ and $m$. This system can move on a smooth horizontal table. The blocks are brought closer to compress the spring and then released. In the subsequent motion,select the true statement$(s)$:
$(a)$ They move in opposite directions with speeds inversely proportional to their masses.
$(b)$ The ratio of their speeds remains constant.
$(c)$ Linear momentum and energy of the system remain conserved.