The diagram depicts two identical spheres $X$ and $Y$. At the start, $X$ is moving at speed $v$ straight towards $Y$. $Y$ 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