Assertion (A): A man standing on a completely frictionless surface can propel himself by whistling.
Reason (R): If no external force acts on a system, its momentum cannot change.
Choose the correct option among the following:
Correct Answer:
(B)
Both A and R are true but R is not a correct explanation of A
First statement can be explained on the basis of Newton's third law of motion, "For every action, there is equal and opposite reaction." While whistling, a man uses his breath as a propellant to propel himself. Momentum is the property that a moving object has due to its mass and motion. Hence, when there is no external force applied on any moving object, its momentum cannot change. Hence, statement A and R both are correct but R is not a correct explanation of A.