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 fires a bullet of mass $65 \, g$ with a velocity of $1300 \, m/s$. The man holding it can exert a maximum force of $169 \, N$ on the gun. The number of bullets he can fire per second will be ............

$A$ force of $50\, dynes$ acts on a body of mass $5\, g$ which is at rest for an interval of $3\, seconds$. The impulse is:

$A$ ball is thrown up at an angle with the horizontal. Then,the total change of momentum by the instant it returns to the ground is

Why does a child feel more pain when she falls down on a hard cement floor,than when she falls on the soft muddy ground in the garden?

$A$ body of mass $5 \,kg$ is moving with a velocity of $\vec{v}=(2 \hat{i}+6 \hat{j}) \,m/s$ at $t=0 \,s$. After time $t=2 \,s$,the velocity of the body is $(10 \hat{i}+6 \hat{j}) \,m/s$. The change in momentum of the body is ......... $kg \cdot m/s$.