Home
Class 12
PHYSICS
A vertical rectangular door with its cen...

A vertical rectangular door with its centre of gravity at `O` (see figure) is fixed on two hinges `A` and `B` along one vertical length side of the door. The entire weight of the door is supported by the hinge `A`. Then the free body force diagram for the door (the arrows indicate the direction of the forces) is

A

B

C

D

Text Solution

Verified by Experts

The correct Answer is:
B
Because of the W of door tries to rotate it clockwise, so, to oppose this normal at hinges produces anticlockwise torque.
Promotional Banner

Topper's Solved these Questions

Similar Questions

Explore conceptually related problems

An accelration produces a narrow beam of protons, each having an initial speed of v_(0) . The beam is directed towards an initially uncharges distant metal sphere of radius R and centered at point O. The initial path of the beam is parallel to the axis of the sphere at a distance of (R//2) from the axis, as indicated in the diagram. The protons in the beam that collide with the sphere will cause it to becomes charged. The subsequentpotential field at the accelerator due to the sphere can be neglected. The angular momentum of a particle is defined in a similar way to the moment of a force. It is defined as the moment of its linear momentum, linear replacing the force. We may assume the angular momentum of a proton about point O to be conserved. Assume the mass of the proton as m_(P) and the charge on it as e. Given that the potential of the sphere increases with time and eventually reaches a constant velue. One the potential of the sphere has reached its final, constant value, the minimum speed v of a proton along its trajectory path is given by

A small ball of mass m and charge q is attached to the bottom end of a piece of negligible mass thread of length l, whose top end is fixed. The system formed by the thread and ball is in vertical plane and is in uniform horizontal magnetic field B, which is perpendicular to the plane of figure and points into the paper The ball is started with a velocity v_(0) from lower most point of circle in a direction perpendicular both to the magnetic induction and to direction of thread. The ball moves along a circular path such that thread remains tight during the whole motion. Neglect any loss of enery. By what factor is the force acting on the thread (tension in thread) at point A is greater than at point C, when speed of the ball is the above stated one?

A bullet of mass 10 g and speed 500 m/s is fired into a door and gets embedded exactly at the centre of the door. The door is 1.0 m wide and weighs 12 kg. It is hinged at one end and rotates about a vertical axis practically without friction. Find the angular speed of the door just after the bullet embeds into it.

A rectangular metal plate ABCD is supported by two hinges P_(1) and P_(2) so that it remains in equilibrium in vertical plane (with line AB vertical) as shown in the figure. The contact forces R_(1) and R_(2) exerted by hinges on the metal plate is best, depicted by

A rod of mass m and length l is hinged at one of its ends A as shown in figure. A force F is applied at a distance x from A . The acceleration of centre of mass varies with x as -

A weightless rigid rod with a load at the end is hinged at point A to the wall so that it can rotate in all directions (Fig). The rod is kept in the horizontal position by a vertical inextensible thread of length 1, fixed at its midpoint. The load receives a momentum in the direction perpendicular to the plane of the figure. Determine the period T of small oscillations of the system.

A thin rod of mass M and length L is bent in a semicircle as shown in figure (a). What is its gravitational force (both magnitude and direction) on a particle with mass m at O the centre of curvature ? (b) what would be the force on m if the rod is in the form of complete circle?

A uniform rod of length (L) and mass (M) is pivoted at the centre. Its two ends are attached to two springs of equal spring constants (k). The springs are fixed to rigid supports as shown in the figure, and the rod is free to oscillate in the horizontal plane. The rod is free to oscillate in the horizontal plane. The rod is gently pushed through a small angle (theta) in one direction and released. The frequency of oscillation is. ? (##JMA_CHMO_C10_009_Q01##).

A uniform thin cylindrical disk of mass M and radius R is attaached to two identical massless springs of spring constatn k which are fixed to the wall as shown in the figure. The springs are attached to the axle of the disk symmetrically on either side at a distance d from its centre. The axle is massless and both the springs and the axle are in horizontal plane. the unstretched length of each spring is L. The disk is initially at its equilibrium position with its centre of mass (CM) at a distance L from the wall. The disk rolls without slipping with velocity vecV_0 = vacV_0hati. The coefficinet of friction is mu. The net external force acting on the disk when its centre of mass is at displacement x with respect to its equilibrium position is.

A simple pendulum of bob of mass m and length L has one of its ends fixed at the centre O of a vertical circle, as shown in the figure. If 0=60^(@) at the point P , the minimum speed u that should be given to the bob so that it completes vetical circle is

ALLEN -TEST PAPER-Exercise (Physics)
  1. A solid hemisphere and a hemisphereical shell are joined as shown. Bot...

    Text Solution

    |

  2. In a system of four thin uniform rods are each of mass inas shown. If ...

    Text Solution

    |

  3. A vertical rectangular door with its centre of gravity at O (see figur...

    Text Solution

    |

  4. A rectangular metal plate ABCD is supported by two hinges P(1) and P(2...

    Text Solution

    |

  5. A uniform beam of weight W is attached to a verical wall by a hings H....

    Text Solution

    |

  6. A body is free to rotate about an axis parallel to y-axis. A force of ...

    Text Solution

    |

  7. A disc of radius R=2m starts rotating wth constant angular acceleratio...

    Text Solution

    |

  8. In the balance machine shown in the figures. Which arm will move downw...

    Text Solution

    |

  9. A uniform disc of mass M =2.50 kg and radius R = 0.20 m is mounted on ...

    Text Solution

    |

  10. A car runs at constant speed around the horizontal race track shown in...

    Text Solution

    |

  11. A man M slides down a curved frictionless track, starting from rest. ...

    Text Solution

    |

  12. An object moves counter-clockwise along the circular path shown below....

    Text Solution

    |

  13. A girl finds herself stuck with her back to the wall of a cylinder rot...

    Text Solution

    |

  14. A puck of mass m is moving in a circle at constant speed on a friction...

    Text Solution

    |

  15. A simple pendulum of bob of mass m and length L has one of its ends fi...

    Text Solution

    |

  16. A small disc can slide in a circular path on a frictionless inclined p...

    Text Solution

    |

  17. Two very small balls A and B of masses 4.0kg and 5.0kg are affixed to ...

    Text Solution

    |

  18. A particle is moving with a velocity of vec(v)=(3hat(i)+4that(j))m//s....

    Text Solution

    |

  19. A particle of mass m oscillates inside a smooth spherical shell of rad...

    Text Solution

    |

  20. An object of mass m is released from rest at a height h above the surf...

    Text Solution

    |