In the following question, statement 1 refers assertion and statement 2 refers reason.
Statement 1: If there is no external torque on a body about its centre of mass, then the velocity of the centre of mass remains constant.
Statement 2: The linear momentum of an isolated system remains constant.
Which one of the following statement is correct?

Options

A. Statement 1 and 2 are true and statement 2 is a correct explanation for statement 1.
B. Statements 1 and 2 are true and statement 2 is not a correct explanation for statement 1.
C. Statement 1 is true and statement 2 is false.
D. Statement 1 is false and statement 2 is true.

Answer

D

Explanation

The absence of external torque does not ensure the absence of external force. If external force is present then the velocity of centre of mass will not remain constant. Thus statement 1 is false.
The linear momentum of an isolated system remains constant because no external force acts on such a system. Thus statement 2 is true.