NEET Physics Question - Laws of Motion

A moongphaliwala sells his moongphali using a weighing machine in an elevator.

Assertion (A): He gains more profit if the elevator is accelerating up.

Reason (R): The apparent weight of an object increases in an elevator while accelerating upward.

(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:

Assertion (A) is true: If the elevator accelerates upwards, the apparent weight \(N = m(g+a)\) of the peanuts increases. If the moongphaliwala sells by the apparent weight reading (e.g., "1 kg" on the scale), they would be selling a *smaller actual mass* \(m_text{actual} = N/(g+a)\) for the same indicated weight. Thus, they gain more profit.

Reason (R) is true: When an elevator accelerates upwards, the normal force (apparent weight) on an object of mass \(m\) is \(N = m(g+a)\), which is greater than its actual weight \(mg\). Reason (R) correctly explains why the apparent weight increases, leading to the profit gain described in (A).

Rankers Physics

Apparent Weight in an Elevator

Solution:

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