Consider the case we throw a very big elastic ball with velocity u at a very small one at rest, as discussed in class. In the nonrelativistic case, the small ball moves off withvelocity $2$u$.$ What is the result, if u $=$ c$/2,$ i$.$e$.,$ half of the speed of light in vacuum?Show that no matter how fast the big ball is thrown at it$,$ the small ball always moves away at less than the speed of light.