Home
Class 11
PHYSICS
A man has fallen into a ditch of width d...

A man has fallen into a ditch of width d and two of his friends are slowly pulling him out using a light rope and two fixed pulleys as shown in figure. Show that the force (assumed equal for both the friends) exerted by each friend on the road increases as the man moves up. Find the force when theman is at a depth h.

Text Solution

Verified by Experts

Given, `m=5 kg of block a`
` ma= 10N`
`rarr a 10/5 = 2m/s^2` ltBrgt As there is no friction between A and B, when the block A mioves, block B remains t rest in its position.

Initial velocity of `a, u=0`
Distance to cover by B to separate out,
`S= 0.2 m`
`Acceleration , a= 2 m/s^2`
We know, `S= ut+ 1/2 at^2`
`rarr 0.2 = 0+1/2 xx 2t^2`
`rarr t^2 =0.2`
`rarr t=0.44 sec~~ 0.45 sec`.
Promotional Banner

Topper's Solved these Questions

  • NEWTON'S LAWS OF MOTION

    HC VERMA|Exercise Objective -2|8 Videos
  • LAWS OF THERMODYNAMICS

    HC VERMA|Exercise Short Answer|14 Videos
  • PHYSICS AND MATHEMATICS

    HC VERMA|Exercise Exercises|34 Videos

Similar Questions

Explore conceptually related problems

Shows a rod PQ of length 20.0 cm and mass 200g suspended through a fixed point O by two threads of lengths 20.0 cm each. A magnetic field of strenght 0.500 T exists in the vicinity of the wire PQ as shown in the figure. The exists in the vicinity of the wire PQ as shown in the figure. The wires conecting PQ with the battery are loose and exert no force on PQ.(a) find the tension in the threads when the switch S is open. (b) A current of 2.0 A is established when the switch S is closed. Find the tension in the threads now.

Figure shows a man of mass 60 kg standing on a light weighting machine kept in a box of mass 30 kg. The box is hanging from a pulley fixed to the ceiling through a light rope, the other end of which is held by the man himself. If the man manages to keep the box at rest, what is the weight shown by the machine? What force should he exert on the rope to get his correct weight on the machine?

A track consists of two circular pars ABC and CDE of equal radius 100 m and joined smoothly as shown in figure.Each part subtends a right angle at its centre. A cycle weighing 100 kg together with rider travels at a constant speed of 18 km/h on the track. A. Find the normal contact force by the road on the cycle when it is at B and at D. b.Find the force of friction exerted by the track on the tyres when the cycle is at B,C and D. c. Find the normal force between the road and the cycle just before and just after the cycle crosses C. d. What should be the minimum friction coefficient between the road and the tyre, which will ensure that the cyclist can move with constant speed? Take g=10 m/s^2

HC VERMA-NEWTON'S LAWS OF MOTION-Exercises
  1. Both the springs shown in figure are untretched. If the block is displ...

    Text Solution

    |

  2. A small block B is placed on another block A of mass 5 kg and length ...

    Text Solution

    |

  3. A man has fallen into a ditch of width d and two of his friends are sl...

    Text Solution

    |

  4. The elevator shown in figure is descending with an acceleration of 2m/...

    Text Solution

    |

  5. A pendulum bobof masss 50 g is suspended from the ceiling of an elevat...

    Text Solution

    |

  6. A person is standing on a weighing machine placed on the floor of an e...

    Text Solution

    |

  7. Find the reading of th spring balance shown in figure. The elevator is...

    Text Solution

    |

  8. A block of 2 kg is suspended from the ceiling through a massless sprin...

    Text Solution

    |

  9. Suppose the ceiling in the previous problem is that the elevator which...

    Text Solution

    |

  10. The force of buoyancy exerted by the atmosphere on a balloon is B in t...

    Text Solution

    |

  11. An empty plastic box of mass m is found to accelerate up at the rate o...

    Text Solution

    |

  12. A force vecF=vecvxxvecA is exerted on a particle in addition to the fo...

    Text Solution

    |

  13. In a simple Atwood machine, two unequal masses m1 and m2 are connected...

    Text Solution

    |

  14. In a simple Atwood machine, two unequal masses m1 and m2 are connected...

    Text Solution

    |

  15. Figure shows a uniform rod of length 30 cm having a mass of 3.0 kg. Th...

    Text Solution

    |

  16. Consider the situation shown in figure. All the surfaces are frictions...

    Text Solution

    |

  17. A constant force F=m2g/s is applied on the block of mass m1 as shown i...

    Text Solution

    |

  18. In figure m1=5 kg, m2=2kg and F=1N. Find the acceleration of either bl...

    Text Solution

    |

  19. Let m1=1 kg, m2=2kg and m3=3kg is figure. Find the acceleration of m1,...

    Text Solution

    |

  20. In the previous problem, suppose m2=2.0kg and m3=3.0 kg. What should b...

    Text Solution

    |