Sphere X undergoes a head-on collision with another identical sphere Y that is initially at rest. Each sphere has a mass of $0.15\,\text{kg}$. Before the collision, sphere X moves at a velocity of $2.0\,\text{m s}^{-1}$ and exerts an impulse of $0.21\,\text{N s}$ on sphere Y. Determine the velocity of sphere X after the collision.
- A$0.60\,\text{m s}^{-1}$ in the opposite direction to Y
- B$0.60\,\text{m s}^{-1}$ in the same direction as Y
- C$1.4\,\text{m s}^{-1}$ in the opposite direction to Y
- D$1.4\,\text{m s}^{-1}$ in the same direction as Y