Question $19($Mandatory$)(5$ points$)$

A ball of mass $10$ kg $,$ moving to the west at a speed of $1\mathrm{.}8\frac{m}{s},$ collides head$-$on with a stationary ball of a smaller diameter and of mass $1\mathrm{.}0$ kg $.$ After the collision, the $1-kg$ ball moves with a speed of $2\mathrm{.}0\frac{m}{s}$ to the west. Which of the following is then true? $($Hint: conservation of momentum, p$10$kg$,$initial $=$ p$10$kg$,$final $+$ p$1$kg$,$ final $).$

D$.$ The $10-kg$ ball moves to the west with a velocity of $1\mathrm{.}6\frac{m}{s}.$

C$.$ The $10-kg$ ball recoils to the east with nearly the same speed as before the collision.

A$.$ The $10-kg$ ball has a velocity of $1\mathrm{.}4\frac{m}{s}$ to the west.

B$.$ The $1-kg$ ball's momentum is $1\mathrm{.}0kg\frac{m}{s}$ to the west.