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.

Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

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.

An object of mass $1 \,kg$ travelling in a straight line with a velocity of $10\, m\, s^{-1}$ collides with,and sticks to,a stationary wooden block of mass $5\, kg$. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also,calculate the velocity of the combined object.

What is the momentum of an object of mass $m$, moving with a velocity $v$?

An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes,state the conditions that must be placed on the magnitude and direction of the velocity. If no,provide a reason.