Three perfectly elastic balls $A,B,$ and $C$ of masses $2,kg,4,kg,$ and $8,kg,$ respectively, move in the same direction with velocities of $4,\frac{m}{s},1,\frac{m}{s},$ and $0\mathrm{.}75,\frac{m}{s},$ respectively. If ball A impinges with ball $B,$ which in turn impinges with ball $C,$ prove that balls A and $B$ will be brought to rest by the impacts.