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A block of mass M is kept in elevator (l...


A block of mass M is kept in elevator (lift) which starts moving upward with constant acceleration b as shown in figure. Initially elevator at rest. The block is observed by two observers A and B for a time interval `t=0` to `t=T`. Observer B is at rest with respect to elevator and observer A is standing on the ground.
Q. According to observer B

A

The work done by gravity on the block is zero

B

the work done by normal reaction on the block is zero

C

the work done by pseudo force on the block is zero

D

all the above are correct

Text Solution

Verified by Experts

The correct Answer is:
D
According to observer B, the displacement of the block is zero, Therefore Work done by gracith is zero
Work donw by normal reaction is zero
Work done by pseudo force is zero.
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