STATEMENT-1
If there is no external torque on a body about its center of mass, then the velocity of the center of mass remains constant.
because
STATEMENT-2
The linear momentum of an isolated system remains constant.
If there is no external torque on a body about its center of mass, then the velocity of the center of mass remains constant.
because
STATEMENT-2
The linear momentum of an isolated system remains constant.
- (A)Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1
- (B)Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1
- (C)Statement-1 is True, Statement-2 is False
- (D)Statement-1 is False, Statement-2 is True✓ Correct
Answer: (D)
Solution
Statement-1 is FALSE: The absence of external torque about the center of mass means angular momentum about the CM is conserved, but this does NOT imply that the velocity of the center of mass remains constant. The CM velocity is determined by the net external force, not torque. For example, a body can have zero torque about its CM while experiencing a net force that accelerates the CM.
Statement-2 is TRUE: This is the law of conservation of linear momentum for an isolated system (no external forces).
Since Statement-1 is false and Statement-2 is true, the answer is (D).
Statement-2 is TRUE: This is the law of conservation of linear momentum for an isolated system (no external forces).
Since Statement-1 is false and Statement-2 is true, the answer is (D).
JEE Advanced · 2007 · 08 Apr 2007 · Paper 2 · Single correct option