Physics - Center of Mass Question with Solution | TestHub

The mass of the ball is $m=100\text{ g}=0.1\text{ kg}$. The initial velocity is $u=20\text{ m/s}$. The final velocity is $v=-15\text{ m/s}$ (taking the initial direction as positive). The change in momentum is $\Delta p=m(v-u)$. So, $\Delta p=0.1\text{ kg}(-15\text{ m/s}-20\text{ m/s})=0.1\text{ kg}(-35\text{ m/s})=-3.5\text{ kg m/s}$. The magnitude of the change in momentum is $|-3.5\text{ kg m/s}|=3.5\text{ kg m/s}$.