Apparent Weight in a Lift – Rankers Physics

Friction: Practice Problem & Solution

Assertion (A): The apparent weight of a person standing in a lift, which speed up is always greater than his true weight. Reason (R): The gravity force due to earth always acts downwards.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Friction. Understanding the underlying formula is key to arriving at the correct answer below:

If the lift speeds up *upwards*, apparent weight \(N = m(g+a)\), which is greater than true weight \(mg\). Under this interpretation, (A) is true. Gravity always acts downwards, so (R) is true. However, (R) does not explain the change in apparent weight due to acceleration.

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