Figures $(a)$,$(b)$,$(c)$ and $(d)$ show the variation of force with time. The impulse is highest in which figure?

Match the items in Column-$I$ with those in Column-$II$.

Column-$I$	Column-$II$
$(1)$ Change in momentum	$(a)$ Force
$(2)$ Rate of change of momentum	$(b)$ Impulse

$A$ bullet of mass $10\,g$ leaves the barrel of a gun with a velocity of $600\,m/s$. If the barrel of the gun is $50\,cm$ long and the mass of the gun is $3\,kg$,then the value of the impulse supplied to the gun will be $.....\,Ns$.

Two trains $A$ and $B$ are running in the same direction on parallel rails such that $A$ is faster than $B$. Packets of equal weight are transferred between them. What will happen due to this?

$N$ bullets,each of mass $m \, kg$,are fired with a velocity $v \, m/s$ at the rate of $n$ bullets per second upon a wall. The reaction force offered by the wall to the bullets is given by:

$A$ $150\, g$ tennis ball coming at a speed of $40\, m/s$ is hit straight back by a bat to a speed of $60\, m/s$. The magnitude of the average force $F$ on the ball,when it is in contact for $5\, ms$,is ........... $N$.