Q10 of 149 Page 192

If the sum of all the forces acting on a body is zero, is it necessarily in equilibrium? If the sum of all the forces on a particle is zero1 is it necessarily in equilibrium?

No, in case of a body it is not necessary to be in equilibrium. As, we can see in the diagram there exists torque in the system though the force is zero. Hence there exists all the rotational parameters.


In case of a particle it remains in equilibrium when the resultant force is zero.


More from this chapter

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8

A heavy particle of mass m falls freely near the earth’s surface. What is the torque acting on this particle about a point 50 cm east to the line of motion? Does this torque produce any angular acceleration in the particle?

 9

If several forces act on a particle, the total torque on the particle may be obtained by first finding the resultant force and then taking torque of this resultant. Prove this. Is this result valid for the forces acting on different particles of a body in such a way that their lines of action intersect at a common point?

 11

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?

 12

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?