Question

Which of the following value depicts the velocity of centre of mass when the system of bodies was initially at rest but started moving due to internal forces. (Ignore any external forces)

1. Zero
2. V₁
3. m₁V₁/m₁+m₂
4. None of the above

Answer 1

Correct Answer - Option 1 : Zero

The correct answer is option 1) i.e. Zero.

CONCEPT:

• Centre of mass: It is the point in a body where all the mass of the body is assumed to be concentrated.
• The velocity of the centre of mass: The velocity of the body as a whole is considered as the velocity of the centre of mass and vice-versa.

EXPLANATION:

• In the absence of an external force, the state of the body does not get affected.
• Hence, the velocity of the body does not change.
• The velocity of the centre of mass of a body is the same as the velocity of the body.
• Since initially, the body was at rest, the value of the velocity of the centre of mass will remain zero.