Question

A billiard ball of mass ‘M’ moving with velocity ‘v1’ collides with another ball of the same mass but at rest. If the collision is elastic the angle of divergence after the collision is

• A. $\frac{V}{2}$
• B. 0º
• C. 30º
• D. 90º
• E. 45º

Answer 1

Answer: (D)

90º

Answer 2

The correct option is (C): 90º.
When two bodies of equal mass collide elastically, their velocities are exchanged along the line of collision.
Thus, the first body will move perpendicular to the line of collision (common normal), and the second body will move along the line of collision.
Therefore, the angle of divergence after the collision is 90°.