Home
Class 11
PHYSICS
The vector sum of a system of non-collin...

The vector sum of a system of non-collinear forces acting on a rigid body is given to be non-zero. If the vector sum of all torques due to the system of forces about a centain point is found to be zero, does this mean that it is necessarily zero about any arbitrary point ?

Text Solution

Verified by Experts

No, not necessary.
We are given that `underset (i) sum overset rarr(F_(i)) !=0`.
However, the sum of torque about a centrain point `O, underset (i)sum overset rarr(r_(i))xx overset rarr(F_(i)) =0`
About any other point O', the sum of torque would be `underset (i)sum (overset rarr(r_(i))-overset rarr(a)) xx overset rarr(F_(i))= underset (i)sum overset rarr(r_(i)) xx overset rarr(F_(i)) - overset rarr(a) xx underset (i)sum overset rarr(F_(i))`
At the second term need not vanish for any value of `overset rarr(a)`, therefore, sum of all the torques about any arbitrary point need not be zero necessarily.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

    PRADEEP|Exercise SHORT ANSWER QUESTIONS II.|2 Videos

  • SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

    PRADEEP|Exercise LONG ANSWER QUESTIONS|26 Videos

  • SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

    PRADEEP|Exercise SHORT ANSWER QUESTIONS I.|2 Videos

  • RAY OPTICS

    PRADEEP|Exercise Problem For Practice(a)|25 Videos

  • THERMODYNAMICS

    PRADEEP|Exercise Assertion- Reason Type Questions|19 Videos

Similar Questions

Explore conceptually related problems

the vector sum of a system of non- collinear forces acting on rigid body is given to be non - zero . If the vector sum of all the torques due to the system of forces about a certain point is found to be zero , does this mean that it is necessarily zero any arbitrary point ?

If the resultant torque of all the forces acting on a body is zero about a point is it necessary that it will be zero about any other point?

Knowledge Check

  • Moment of concurrent forces about any point is constant. If vector sum of all concurrent forces is zero, then moment of all the forces about any point is also zero.

    A
    If both Accertion and Reason are true and the reason is correct explanation of the Assertion.
    B
    If both Assertion and Reason are true but reason is not the correct explanation of Assertion.
    C
    If Assertion is true, but the Reason is false.
    D
    If Assertion is false but the Reason is true.

  • If the torque acting on a rigid body, under the application of a force, is zero then it's

    A
    linear momentum is conserved
    B
    angular momentum is not conserved
    C
    energy is conserved
    D
    angular momentum is conserved

  • If the torque acting on a rigid body, under the application of a force, is zero then it's

    A
    linear momentum is conserved
    B
    angular momentum is not conserved
    C
    energy is conserved
    D
    angular momentum is conserved

    • Similar Questions

    Explore conceptually related problems

    If the angular momentum of a body is found to be zero about a point is it necessary that it will also be zero about a different point?

    A body is in translational equilibrium under the sctin of coplanar forces. If the torque of these force is zero about a point is it necessary that it will also be zero abut any other point?

    When is the sum of two non zero vectors is zero ?

    The sum of all the external forces on a system of particles is zero. Which of the following must be true for the system of particles ?

    Assertion : Angular momentum of sun and planet system about any point remains constant Reason : Two equal and opposite forces will acts on them. Net torque of these two set of forces about any point is zero.

    Home
    Profile