A person standing on the floor of an elevator drops a coin. The coin reaches the floor in time t₁ if the elevator is at rest and in time t₂ if the elevator is moving uniformly. Then (a) t₁ = t₂ (b) t₁ t₂ depending upon whether the lift is going up or down (c) t₁ t₂

Answer: (a). In a lift moving with uniform velocity, the frame is inertial, so the coin's acceleration relative to the floor is still g. The coin starts at rest relative to the floor and falls the same height h, so t = √(2h/g) in both cases. So the answer is (a) t₁ = t₂.

A person standing on the floor of an elevator drops a coin. The coin… | NEET 2019

Q44NEET 2019Easy

Motion Under Gravity

A person standing on the floor of an elevator drops a coin. The coin reaches the floor in time $t_1$ if the elevator is at rest and in time $t_2$ if the elevator is moving uniformly. Then

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Answer: (a)

In a lift moving with uniform velocity, the frame is inertial, so the coin's acceleration relative to the floor is still $g$ .
The coin starts at rest relative to the floor and falls the same height $h$ , so $t = \sqrt{2h/g}$ in both cases.
So the answer is (a) $t_1 = t_2$ .

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