From a rifle of mass $4\, kg$,a bullet of mass $50\, g$ is fired with an initial velocity of $35\, m\, s^{-1}$. Calculate the initial recoil velocity (in $m/s$) of the rifle.

How much momentum will a dumbbell of mass $10\, kg$ transfer to the floor if it falls from a height of $80\, cm$? Take its downward acceleration to be $10\, m \,s^{-2}$.

According to the third law of motion,when we push on an object,the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside,it will probably not move. $A$ student justifies this by answering that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move.

Two objects,each of mass $1.5\, kg$,are moving in the same straight line but in opposite directions. The velocity of each object is $2.5\, m/s$ before the collision during which they stick together. What will be the velocity (in $m/s$) of the combined object after collision?

Which of the following has more inertia: $(a)$ a rubber ball and a stone of the same size? $(b)$ a bicycle and a train? $(c)$ a five-rupee coin and a one-rupee coin?

$A$ hockey ball of mass $200 \,g$ travelling at $10 \,m \,s^{-1}$ is struck by a hockey stick so as to return it along its original path with a velocity of $5 \,m \,s^{-1}$. Calculate the magnitude of the change in momentum of the hockey ball due to the force applied by the hockey stick.