Perfectly Elastic Collision
### Conditions
Momentum conservation:
$$m_1u_1+m_2u_2=m_1v_1+m_2v_2$$
Kinetic energy conservation:
$$\frac{1}{2}m_1u_1^2+\frac{1}{2}m_2u_2^2=\frac{1}{2}m_1v_1^2+\frac{1}{2}m_2v_2^2$$
### Final Velocities
$$v_1=\frac{m_1-m_2}{m_1+m_2}u_1+\frac{2m_2}{m_1+m_2}u_2$$
$$v_2=\frac{2m_1}{m_1+m_2}u_1+\frac{m_2-m_1}{m_1+m_2}u_2$$
### Usage
- Used in ideal collision problems.