Question

If a body of mass M collides against a wall with velocity V and rebounds with the same velocity, its change of momentum is:

• A. Zero
• B. $Mv$
• C. $-Mv$
• D. $-2Mv$

Answer 1

The correct option is D

$-2Mv$

Explanation for the correct option

(D) -2Mv

Step 1: Given data

Mass of a body M.

Initial Velocity V.

Final velocity -V.

Step 2: Finding momentum

By the formula of Momentum $=mass\times velocity$

Therefore Initial momentum =$M\times v=Mv$

Final momentum $=M\times -v=-Mv$

Thus to calculate the change in momentum$=(-Mv)-Mv=-2Mv$

Therefore the change in momentum is $-2Mv.$

Hence if a body of mass M collides against a wall with velocity V and rebounds with the same velocity, its change of momentum is $-2Mv.$ Hence option (d) is correct.