Hi I'm stuck on a problem with a elastic collision.
wagon1 has the mass 1 kg and the velocity 3 m/s, collides with wagon which has the mass 2 kg and is standing still, what are the wagon's velocity after the collision?
Momentum is conserved, so $\displaystyle m_1v_1+m_2v_2=m_1v_{init}$, where $\displaystyle m_1$ and $\displaystyle m_2$ are the masses, $\displaystyle v_{init}$ is the initial velocity, and $\displaystyle v_1$ and $\displaystyle v_2$ are the final velocities. Since the collision is elastic, kinetic energy is also conserved, so $\displaystyle \frac{1}{2}m_1v_1^2+\frac{1}{2}m_2v_2^2=\frac{1}{2 }m_1v_{init}^2$.
I think you can solve it from there. You should get $\displaystyle v_1=-1$ and $\displaystyle v_2=2$, so wagon 1 bounces and is coming back the other direction at 1 m/s, and wagon 2 moves at 2 m/s.
- Hollywood