Question

Assertion: The accelerated motion of an object may be due to change in magnitude of velocity or direction of velocity of both.
Reason: Acceleration can be produced only by change in the magnitude of the velocity.
A. Both Assertion and Reason are correct and Assertion is the correct explanation for Reason.
B. Both Assertion and Reason are correct and Assertion is not the correct explanation for Reason.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Recall the concept of accelerated motion of an object. Check the condition for the motion of an object to be accelerated motion. Recall the relation between the velocity and acceleration of an object. Check which factors related to velocity of an object are responsible to produce acceleration of that object. Hence, choose the correct option.

Complete answer:
We know that the accelerated motion of an object is the motion in which the acceleration of an object is changing with time. The acceleration of an object is the rate of change of velocity of the object with time. As the velocity of an object is a vector physical quantity, it has magnitude as well as direction.

If the magnitude of velocity of an object or direction of velocity of an object or both magnitude and direction of velocity of an object are changed then there is a change in acceleration of that object.

The example of this is the circular motion in which the change in direction of velocity produces acceleration. Hence, if the magnitude or direction of both of the velocity of the object are changed continuously the motion of that object is the accelerated motion.Therefore, Assertion is correct.

From the above information, we know that acceleration can be produced when the magnitude of velocity of an object or direction of velocity of an object or both magnitude and direction of velocity of an object are changed.

Therefore, the statement acceleration can be produced only by change in the magnitude of the velocity is incorrect. Hence, the Reason is incorrect. Hence, the Assertion is correct but the Reason is incorrect.

Hence, the correct option is C.

Note: The students should not think that in the accelerated motion of an object velocity of the object always increases. The students should keep in mind that during the acceleration motion of an object, the acceleration of the object is continuously changing which means that the velocity of the object may increase or decrease.