Question

A body of mass ‘M’ collides against a wall with a velocity v and retraces its path with the same speed. The change in momentum is (take initial direction of velocity as positive)

• A. Zero
• B. 2Mv
• C. Mv
• D. – 2 Mv

Answer 1

Answer: (D)

– 2 Mv

Answer 2

Change in momentum

$= m \vec { v } _ { 2 } - m \vec { v } _ { 1 }$ $= - m v - m v = - 2 m v$