The diagram illustrates two identical spheres $X$ and $Y$. At the start, $X$ is travelling directly towards $Y$ with speed $v$, while $Y$ is at rest. The spheres undergo an elastic collision. What happens?
- A$X$ moves with speed $\frac{1}{2}v$ to the right; $Y$ moves with speed $\frac{1}{2}v$ to the right
- B$X$ moves with speed $v$ to the left; $Y$ remains stationary
- C$X$ moves with speed $\frac{1}{2}v$ to the left; $Y$ moves with speed $\frac{1}{2}v$ to the right
- D$X$ stops; $Y$ moves with speed $v$ to the right