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?

Question

a) the balls stick and move together
b) the ball separate immediately
c) the first ball stops while the other ball start moving
d) the two balls travel off in opposite directions, 180 degree apart.

Answer 1

Inelastic collision means the two objects do not rebound and move at a common velocity.
Yes, choice a is correct.