Question

Ball A moving at 12 m/s collides elastically with ball B, initially at rest as shown. If both balls have the same mass, then what is the final velocity of ball A?

• A. 3 m/s
• B. 6 m/s
• C. 9 m/s
• D. 12 m/s

Hint:

In elastic collisions with equal masses, the velocity of the first object after collision is a fraction of its initial velocity based on the angle of the collision.

Answer 1

The Correct Option is B

In an elastic collision, the relative velocities of approach and separation are equal.
For two objects with equal mass, the final velocities can be determined using the following equations derived from the law of conservation of momentum and energy.
For ball A: \[ v_A = v_A' \cos \theta + v_B' \cos \phi \] Where \( \theta = 60^\circ \) is the angle of the collision, and given that the collision is elastic, the final velocity of ball A will be 6 m/s.

Thus, the correct answer is (b).