Question

Assertion The centre of mass of a body must lie on the body.
Reason The centre of mass of a body lie at the geometric centre of body.

• A. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is correct.

Answer 1

Answer: (D)

The centre of mass of a body may lie on or outside the body.

Hence, in Fig. (a), centre of mass is on the body and in Fig. (b), centre of mass does not lie on the body.
The centre of mass of an object is the average position of all the parts of the system, weighted according to their masses. Therefore, centre of mass of body lie at the geometric centre of body.
Therefore, Assertion is incorrect but Reason is correct.