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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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ALLEN-TEST PAPER-Exercise (Physics)
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  2. A plank of mass 2 kg and length 1 m is placed on horizontal floor.A sm...

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  3. A block is moving along y-axis with velocity vec(v)(A)=4hat(j) on a pl...

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  4. A block is projected up along the line of greatest slope of an incline...

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  5. A metal block is resting on a rough wooden surface. A horizontal force...

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  6. A Body intially at rest, starts moving along x-axis in such a way so t...

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  7. A particle is shifted from A to B and then from B to C where A,B and C...

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  8. Velocity of a stone projected, 2 seconds before it reaches the maximum...

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  9. A particle is moving along the x-axis whose position is given by x= 4...

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  10. A particle moves 21m along the vector 6hat(i)+2hat(j)+3hat(k) , then 1...

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  11. A particle is falling freely under gravity. In frist t secnd it covers...

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  12. For a particle moving along x-axis, speed must be increasing for the f...

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  13. A car of mass 1000kg moves from point A to B. If kinetic energy of ca...

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  14. Two bodies of masses m(1) and m(2) are acted upon by a constant force ...

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  15. A body (initially at rest is falling under gravity. When it loses a gr...

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  16. The graph below shows how the force on a mass depends on the position ...

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  17. A particle with total energy E moves in one direction in a region wher...

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  18. Consider the folllowing graph of potential energy (U) vs position (x) ...

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  19. A chain of length L and mass M is held on a frictionless table with (1...

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  20. A force of magnitude of 30N acting along hat(i)+hat(j)+hat(k), displac...

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