Home
Class 11
PHYSICS
A child sits stationary at one end of a ...

A child sits stationary at one end of a long trolley moving uniformly with a speed V on a smooth horizontal floor. If the child gets up and runs about on the trolley in any manner, what is the speed of the CM of the (trolley + child) system ?

A

increases

B

decreases

C

remains same

D

changes

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • MOTION OF SYSTEM OF PARTICLES AND BODIES

    PREMIERS PUBLISHERS|Exercise OTHER IMPORTANT QUESTIONS & ANSWER (VERY SHORT ANSWER QUESTIONS)|24 Videos
  • MOTION OF SYSTEM OF PARTICLES AND BODIES

    PREMIERS PUBLISHERS|Exercise OTHER IMPORTANT QUESTIONS & ANSWER (SHORT ANSWER QUESTIONS)|38 Videos
  • MOTION OF SYSTEM OF PARTICLES AND BODIES

    PREMIERS PUBLISHERS|Exercise TEXTBOOK QUESTIONS & ANSWERS (NUMERICAL PROBLEMS)|12 Videos
  • LAW OF MOTION

    PREMIERS PUBLISHERS|Exercise OTHER IMPORTANT QUESTIONS & ANSWERS (VI Numerical Problems)|62 Videos
  • NATURE OF PHYSICAL WORLD AND MEASUREMENT

    PREMIERS PUBLISHERS|Exercise OTHER IMPORTANT QUESTIONS & ANSWERS (III. Short Answer Questions.)|24 Videos

Similar Questions

Explore conceptually related problems

when a child sits stationary at one end of a long trolley moving uniformly with some speed on a smooth horizontal plane. The speed of the centre of mass of system (child and trolley),

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod and the magnetic field are in three mutually perpendicular directions. A galvonometer G connects the rails through a switch K. Length of rod = 15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0mOmega . Assume the field to be uniform. a. Suppose K is open and the rod is moved with a speed of 12cms^(-1) in the direction shown. Give the polarity and magnitude of the induced emf. b. Is there an excess charge built up at the ends of the rods when K is open? What if K is closed? c. With K open and the rod moving uniformly, there is no net force on the electrons in the rod PQ eventhough they do experience magnetic force due to the motion of the rod. Explain. d. What is the retarding force on the rod when K is closed? e. How much power is required (by an external agent) to keep the rod moving at the same speed (=12cms^(-1)) when K is closed? How much power is required when K is open? f. How much power is dissipated as heat in the closed circuit? What is the source of this power? g. What is the induced emf in the moving rod if the magnetic field is parallel to the rails instead of being perpendicular?

One end of string of length L is connected to a particle of mass 'm' and the other end is connected to small peg on a smooth horizontal table.If the particle moves in circle with speed 'v'. te net force on the particle (directed towards centre ) will be (T represents the tension in thestring)

On a long horizontally moving belt (Fig.), a child runs to and fro with a speed 9 km h^(-1) (with respect to the belt) between his father and mother located 50 m apart on the moving belt. The belt moves with a speed of 4 km h^(-1) . For an observer on a stationary platform outside, what is the (a) speed of the child running in the direction of motion of the belt ?. (b) speed of the child running opposite to the direction of motion of the belt ? (c ) time taken by the child in (a) and (b) ? Which of the answers alter if motion is viewed by one of the parents ?

A string of linear mass density 0.5 g cm^-1 and a total length 30 cm is tied to a fixed wall at one end and to a frictionless ring at the other end. The ring can move on a vertical rod. A wave pulse is produced on the string which moves towards the ring at a speed of 20 cm s^-1 . The pulse is symmetric about its maximum which is located at a distance of 20 cm from the end joined to the ring. (a) Assuming that the wave is reflected from the ends without loss of energy, find the time taken by the string to regain its shape. (b) The shape of the string changes periodically with time. Find this time period. (c) What is the tension in the string ?

Consider a long, straight wire of cross-sectional area A carrying a current i. Let there be n free electrons per unit volume. An observed places himself on a trolley moving in the direction opposite to the current with a moving in the direction opposite to the current with a speed (v= i/nAe) and separated from the wire by a distance r. The magnetic field seen by the observer is very nearly

Figure shows a light rod of length l rigidly attached to a small heavy block at one end and a hook at the other end. The system is released from rest with the rod in a horizontal position. There is a fixed smooth ring at a depth h below the initial position of the hook and the hook gets into the ring as it reaches there. What should be the minimum value of h so that the block moves in a complete circle about the ring?

A smooth ring A of mass m can slide on a fixed horizontal rod. A string tied to the ring passes over a fixed pulley B and carries a block C of mass M(=2m) as shown in figure. At an instant the string between the ring and the pulley makes an angle theta with the rod. a. Show that, if the ring slides with a speed v, the block descends with speed v cos theta , b. With what acceleration will the ring starts moving if the system is released from rest with theta= 30^0

A block is mass m moves on as horizontal circle against the wall of a cylindrical room of radius R. The floor of the room on which the block moves is smooth but the friction coefficient between the wall and the block is mu . The block is given an initial speed v_0 . As a function of the speed v write a. the normal force by the wall on the block. b. the frictional force by the wall and c. the tangential acceleration of the block. d. Integrate the tangential acceleration ((dv)/(dt)=v(dv)/(ds)) to obtain the speed of the block after one revoluton.

PREMIERS PUBLISHERS-MOTION OF SYSTEM OF PARTICLES AND BODIES-OTHER IMPORTANT QUESTIONS & ANSWER (MULTIPLE CHOICE QUESTIONS)
  1. A point in the system at which whole mass of the body is supposed to b...

    Text Solution

    |

  2. The location of the centre of mass of a sphere is at:

    Text Solution

    |

  3. A child sits stationary at one end of a long trolley moving uniformly ...

    Text Solution

    |

  4. Centre of mass of the body practically coincides with:

    Text Solution

    |

  5. A fly wheel of moment of inertia 4xx10^(-3)kgm^(2) is makign 10 revolu...

    Text Solution

    |

  6. The mass of a body measures:

    Text Solution

    |

  7. Identify the vector quantity among the following:

    Text Solution

    |

  8. Angular momentum is ………………….. Vector.

    Text Solution

    |

  9. A diver in a swimming pool bends his head before diving. It

    Text Solution

    |

  10. Which one of the following statement is not correct?

    Text Solution

    |

  11. When a steady torque is acting on a body, the body:

    Text Solution

    |

  12. A circular turn table has a block of ice placed at its centre. The sys...

    Text Solution

    |

  13. The curve between log(e) L and log(e) P is (L is the angular momentum ...

    Text Solution

    |

  14. A couple produces motion.

    Text Solution

    |

  15. A wheel is rotating at the rate of 10 revolutions per second about an ...

    Text Solution

    |

  16. A particle is moving with a contant velocity along a line parallel to ...

    Text Solution

    |

  17. A particle undergoes uniform circular motion. The angular momentum of ...

    Text Solution

    |

  18. A particle is confined to rotate in a circular path decreasing linear ...

    Text Solution

    |

  19. A solid sphere is rotationg in free space. If the radius of the sphere...

    Text Solution

    |

  20. A couple is acting on a two particle system. The resultant motion will...

    Text Solution

    |