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A block (A) of mass 45kg is placed on an...

A block (A) of mass `45kg` is placed on another block (B) of mass `123 gk. Now block (B) is displaced by extenal agent by `50 cm` horizontally towards right. During the same time block (A) just reaches to the left end of block (B), Initial and final positions are shown in figures . the work done on block (A) in ground frame is
,

A

`-18 J`

B

`18 J`

C

`36 J`

D

`-36 J`.

Text Solution

Verified by Experts

The correct Answer is:
B
There is slip, so maximum friction will act on A the direction of motion (or towards right)

`f-mu mg=0.2xx45xx10 =90 N`
`S=40-10-10=20 cm =0.2`
`W=fS =18 J`.
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