Force is the mutual interaction between the bodies according to:

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?

$Assertion$ : $A$ quick collision between two bodies is more violent than a slow collision,even when the initial and final velocities are identical.
$Reason$ : The rate of change of momentum is greater in the first case.

If impulse $I$ varies with time $t$ as $I \text{ (kg m s}^{-1}) = 20 t^2 - 40 t$. The change in momentum is minimum at ........... $s$.

$A$ particle of mass $m$,initially at rest,is acted on by a force $F = F_0 \left\{ {1 - {{\left( {\frac{{2t - T}}{T}} \right)}^2}} \right\}$ during the interval $0 \leq t \leq T$. The velocity of the particle at the end of the interval is:

$A$ body of mass $M$ hits normally a rigid wall with velocity $V$ and bounces back with the same velocity. The impulse experienced by the body is