Home
Class 11
PHYSICS
A lift is moving downwards with an accel...

A lift is moving downwards with an acceleration equal to `g`. A block of mass `m` , kept on the floor of the lift of friction coefficient `mu` , is pulled horizontally . The friction acting on the block is

A

`mu Mg`

B

`2 mu M g`

C

zero

D

Mg

Text Solution

Verified by Experts

The correct Answer is:
C
(c ) For downward motion of lift,` R=m(g-a)`
Here, a=g
`therefore R=0`
So, `F=muR=0`
Promotional Banner

Topper's Solved these Questions

  • LAWS OF MOTION

    DC PANDEY|Exercise Match the columns|7 Videos

  • KINEMATICS 1

    DC PANDEY|Exercise INTEGER_TYPE|15 Videos

  • LAWS OF THERMODYNAMICS

    DC PANDEY|Exercise Level 2 Subjective|18 Videos

Similar Questions

Explore conceptually related problems

A block of mass m is kept on a horizontal table. If the static friction coefficient is mu ., find the frictional force acting on the block.

A lift is moving down with an acceleration equal to the acceleration due to gravity. A body of mass M kept on the floor of the lift is pulled horizontally If the coefficient of friction is mu then the frictional resistance offered by the body is .

A block of mass m lying on a rough horizontal surface of friction coefficient mu is pulled by a force F as shown , the limiting friction between the block and surface will be

A body of mass m kept on the floor of a lift moving downwards is pulled horizontally. If mu is the coefficient of friction between the surface in contact, then

A block of mass M is sliding down the plane. Coefficient of static friction is mu_(s) and kinetic friction is mu_(k) . Then friction force acting on the block is :

A lift is moving downwards. A body of mass 2 kg kept on the floor is pulled horizontally and is in motion. If the coefficient of friction between the body and floor is 1 // 2 , find the friction acting on the body if (a) lift is moving with a uniform velocity and (b) lift is moving with acceleration 5 m//s^(2) in the downward direction.

An observer is standing inside a lift moving upwards with an acceleration a. A mass m is lying on the floor of the lift. Find the normal reaction between the block and the floor.

A lift is moving upwards with an acceleration of 2m//sec^(2) . Inside the lift a 4kg block is kept on the floor. On the top of it , 3kg block is placed and again a 2kg block is kept on the 3kg . Calculator : (i) contact force between 2kg block and the 3kg block. (ii) contact force between 4kg block and floor of the lift. Draw the free body diagrams properly & take g=10m//sec^(2)

A lift moving with a uniform velocity v in which a block of mass m is lying .The friction force offered by the when coefficient of friction is mu = 0.5 will be

DC PANDEY-LAWS OF MOTION-Medical entrances gallery
  1. A 3 kg block is placed over a 10 kg block and both are palced on a smo...

    Text Solution

    |

  2. A 60 kg person is weighed by a balance as 54 kg in a lift which is acc...

    Text Solution

    |

  3. A lift starts from rest with a constant upward acceleration It moves 1...

    Text Solution

    |

  4. Two masses M and M/ 2 are joint together by means of a light inextensi...

    Text Solution

    |

  5. A body of mass m(1) moving with uniform velocity of 40 m/s collides w...

    Text Solution

    |

  6. A lift is moving downwards with an acceleration equal to g. A block of...

    Text Solution

    |

  7. An inclined plane of height h and length l have the angle of inclinati...

    Text Solution

    |

  8. A coin is dropped in a lift. It takes time t(1) to reach the floor whe...

    Text Solution

    |

  9. If a body of mass 5 kg initially at rest is acted upon by a force of 5...

    Text Solution

    |

  10. A 60 kg body is pushed with just enough force to start it moving acros...

    Text Solution

    |

  11. A 40 kg slab rests on a frictionless floor . A 10 kg block rests on to...

    Text Solution

    |

  12. A body of mass 0.25 kg is projected with muzzle velocity 100ms^(-1) fr...

    Text Solution

    |

  13. A rocket with a lift-off mass 3.5xx10^4 kg is blasted upwards with an ...

    Text Solution

    |

  14. A marble block of mass 2 kg lying on ice when given a velocity of 6m//...

    Text Solution

    |

  15. Four blocks of the same mass m connected by cords are pulled by a forc...

    Text Solution

    |

  16. A body is hanging from a rigid support. by an inextensible string of l...

    Text Solution

    |

  17. A block A with mass 100kg is resting on another block B of mass 200kg....

    Text Solution

    |

  18. A machine gun fires a bullet of mass 40 g with a velocity 1200 ms^-1. ...

    Text Solution

    |

  19. A monkey of 25 kg is holding a vertical rope. The rope does not break ...

    Text Solution

    |

  20. A body of weight 50 N placed on a horizontal surface is just moved by ...

    Text Solution

    |