Home
Class 11
PHYSICS
A rigid rod of length 2 L is acted upon ...

A rigid rod of length `2 L` is acted upon by some forces. All forces labelled `F` have the same magnitude. Which cases have a non-zero net torque acting on the rod about its centre ?
.

A

I and II only

B

II and III only

C

I and III only

D

The net torque is zero in all cases.

Text Solution

Verified by Experts

The correct Answer is:
A
By sign convention anticlockwise moment (or torque) is taken as positive while clockwise moment (or torque) is taken as negative.
In cae I, net torque about its center is
`tau= F xx L + F xxL = 2FL`

In Case II, net torque about it center is
`tau=F xx L + F xx L/2 + F xx L = 5/2 FL`

In case III, net torque about its center is
`tau=-F xx L + F xx L/2- F xx L/2 + F xx L=0`
Promotional Banner

Topper's Solved these Questions

  • SYSTEM OF PARTICLES AND ROTATIONAL MOTIONS

    NCERT FINGERTIPS|Exercise Moment Of Inertia|7 Videos

  • SYSTEM OF PARTICLES AND ROTATIONAL MOTIONS

    NCERT FINGERTIPS|Exercise Theorems Of Perpendicular And Parallel Axes|5 Videos

  • SYSTEM OF PARTICLES AND ROTATIONAL MOTIONS

    NCERT FINGERTIPS|Exercise Torque And Angular Momentum|11 Videos

  • PRACTICE PAPERS

    NCERT FINGERTIPS|Exercise Practice Paper 3|50 Videos

  • THERMAL PROPERTIES OF MATTER

    NCERT FINGERTIPS|Exercise Assertion And Reason|10 Videos

Similar Questions

Explore conceptually related problems

In which of the following cases the net force acting on the body is not zero?

A homogeneous rod of length L is acted upon by two forces F_(1) and F_(2) applied to its ends and directed opposite to each other. With what force F will the rod be stretched at the cross section at a distance l from the end where F_(1) is applied?

A uniform metallic rod PQ of length 2 m is acted upon by two forces A and B along the directions as shown in the figure. Find the magnitude and position of the resultant normal force that acts on the rod.

A rectangular loop is acted upon by two forces of same magnitude but opposite directions. The net force acting on the loop is

If the external forces acting on a system have zero resultant, the centre of maas

If the external forces acting on a system have zero resultant, the centre of mass

A straight rod AB of mass M and length L is placed on a frictionless horizontal surface. A force having constant magnitude F and a fixed direction start acting at the end A. The rod is initially prependicular to the force. The initial acceleration of end B is

A straight rod AB of mass M and length L is placed on a frictionless horizontal surface. A horizontal force having contstant magnitude F and fixed direction starts acting at the end A . The rod is initially perpendicular to the force. Find the initial acceleration of end B .