Question

When does a body rotate? state one way to change


the direction of rotation of a body .Give a...

Answer 1

when it is pivoted at a point and force is applied in a specific direction. it can be changed by changing the direction or point of application of force

Answer 2

Explanation:

The body rotates due to torque and the rotation direction can be changed if we apply retarded torque or change in torque direction.

As per Newton's first law, a body will remain in its state of rest or motion until or unless an external force is applied on the body. The external force used to rotate a body is named as torque. Torque can also be defined as the work done by the body to cover a certain distance and it is also termed as moment of force.

The torque is represented by formula

$\bold{\tau=F d \sin \theta}$

Where, τ  is Torque, F is the external force applied to rotate the body, d is the perpendicular distance from its central point and θ is the rotation angle.

So in order to change the rotation direction, reverse torque need to be applied over the body.

The best example for changing the rotation due to torque is the bar magnet which rotates under the magnetic field. In this case, the magnetic field is the external force which changes the north and south pole of bar magnet to show the direction in sea.