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Byju's Answer

Standard IX

Physics

Second Law of Motion

Assertion :Wh...

Question

Assertion :When a man is standing in a lift which is either at rest or moving up or moving down, with uniform speed, he does not find any apparent change in his weight. Reason: The reaction of the floor of the lift is equal to his weight.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

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Assertion is correct but Reason is incorrect

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Both Assertion and Reason are incorrect

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Solution

The correct option is D Both Assertion and Reason are incorrect

In (a) $W = m g = N$
In (b) $W = m g = N$
In (c) $W = m (g + a) = N$
Which going upwards & $W = m (g - a)$ while going down wards.
So, In both first two cases there is no change in weight due to no acceleration of lift. While in third cases, there is apparent weight concept.

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