The time in which a force of $2 \, N$ produces a change of momentum of $0.4 \, kg \cdot m/s$ in a body is ......... $s$.

When the speed of a moving body is doubled:

Two bodies $A$ and $B$ collide as shown in Fig. $(i)$ and $(ii)$. Which statement is true?

An athlete runs for some distance before taking a long jump. Why?

If two balls each of mass $0.06 \,kg$ moving in opposite directions with speed $4 \,m/s$ collide and rebound with the same speed,then the impulse imparted to each ball due to the other is ........... $kg \cdot m/s$.

$A$ machine gun can fire $200$ bullets $\min^{-1}$. If $35 \ g$ bullets are fired at a speed of $750 \ m \ s^{-1}$, the average force exerted by the gun on the bullets is, (in $N$)