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A block is moving along y-axis with velo...

A block is moving along `y-`axis with velocity `vec(v)_(A)=4hat(j)` on a plank relative to ground and the plank is moving along `x-`axis with velocity `vec(v)_(P)=3hat(i)` at any instant of time. The unit vector in dirction of fricition force acting on block at this moment is `:-`

A

`(3hat(i)+4hat(j))/(5)`

B

`(3hat(i)-4hat(j))/(5)`

C

`(-3hat(i)+4hat(j))/(5)`

D

`(-3hat(i)-4hat(j))/(5)`

Text Solution

Verified by Experts

The correct Answer is:
B
`vec(f)=-hat(v)_(rel)=-vec(v)_(AP)=-[(4hat(i)-3hat(j))/(5)]=(3hat(i)-4hat(j))/(5)`
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