A ball of mass 0 . 15   kg hits the wall with its initial speed of 12   m   s - 1 and bounces…

Given: $m=1.5 \mathrm{kg} \& u=12 \mathrm{m} {\mathrm{s}}^{-1}$

Change in the momentum of the ball after the collision$=2mv$

$=2\times 1.5\times 12$

$=36 \mathrm{N} \mathrm{s}$

As the force applied during collision is equal to $100 \mathrm{N}$ and if $t$ is the duration of collision, so

$100\times t=\Delta p$

$\Rightarrow t=\frac{36}{100} \mathrm{s}$

$t=36\times {10}^{-2} \mathrm{s}=0.036 \mathrm{s}$