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An observed and a vehicle, both starts m...

An observed and a vehicle, both starts moving together from rest with accelerations `5 m//s^(2)` and `2 m//s^(2)`, respectively. There is a `2 kg` block on the floor of the vehicle, and `mu = 0.3` between their surfaces. Find the work done by friction on the block with respect to the running observer, during first `2` seconds of the motion.
.

A

24 J

B

-24 J

C

16 J

D

-16 J

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The correct Answer is:
B
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