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NEETPhysicsMotion in One Dimension

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): If a lift is accelerating vertically upwards, a ball dropped from its ceiling takes less time to hit the floor compared to when the lift is stationary. Reason (R): The acceleration of the dropped ball with respect to the ground is g downwards. In the light of the above statements, choose the most a

Options

  1. ABoth Assertion and Reason are true and Reason is the correct explanation of Assertion.
  2. BBoth Assertion and Reason are true but Reason is not the correct explanation of Assertion.
  3. CAssertion is true but Reason is false.
  4. DAssertion is false but Reason is true.

Correct answer

B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

Step-by-step solution

Assertion (A) is true: When the lift is accelerating upwards with acceleration a , the relative acceleration of the ball with respect to the lift is a_ rel = g - (-a) = g + a (downwards). Since the effective acceleration (g + a) is greater than g , the time taken to hit the floor t = 2h g+a is less than the time taken in a stationary lift t = 2h g . Reason (R) is true: Once the ball is dropped, it is under free fall. Its acceleration with respect to the ground is simply the acceleration due to gravity g downwards,

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