Question

Two balls have the same mass. One ball moving along the positive x-axis and the other ball moving along the positive y-axis undergo perfectly inelastic collision. What can you say about the motion of the balls after the collision?

Answer 1

\[m \dot x_1 + m (0) = 2 m \dot x_2 \implies \dot x_2 = \frac{1}{2} \dot x_1\]
\[m \dot y_1 + m (0) = 2 m \dot y_2 \implies \dot y_2 = \frac{1}{2} \dot y_1\]

Answer 2

symmetry?