Torque

Torque:-

The turning effect produced by a force acting on a body around an axis or point is called ‘Torque’.

Mathematically torque can be defined as the product of force applied and its perpendicular distance from the center axis.

S.I unit of torque is N-m (Newton-meter)

Centripetal and Centrifugal Forces

Centripetal and Centrifugal forces:-

Centripetal and Centrifugal forces are two equal and opposite forces acting on a body moving in a defined circular or elliptical path.

A stone tied with a thread rotated in a circular path is the best example of centrifugal and centripetal forces. The rotating motion of stone produces a force due to moment of inertia, which acts radially outwards, is called ‘Centrifugal Force’.

-Similarly an equal and opposite force is produced through the thread which acts inwards and stops the stone getting  thrown out in the air due to centrifugal force. This equal and opposite force is called ‘Centripetal Force’.

A balance between centrifugal and centripetal force is necessary for continuous and defined circular motion of stone. If we increase the rotational speed of stone beyond a certain limit, the thread will reach upto its maximum tension and get broken. And the stone will be thrown out in the air.

For Example:-

Rotation of planets around sun: - All planets are rotating in a defined elliptical path due to balanced centrifugal and centripetal forces. The gravitational force between planet and sun acts as centripetal force in order to balance the centrifugal force produces by the motion of planet.

Centrifugal force =  mass x angular acceleration

                                            =   m × ω²r

                                                 =  m ω²r

Couple of Forces

Couple:-

Two Parallel forces with equal magnitude but acting in opposite directions are called as ‘Couple’.

A couple acting on a body produce rotary motion in the body.

Moment Of Force

Moment of Forces:-

When force is applied on body which is free to rotate about a fulcrum point, a rotational moment is produced by the applied force. This rotational effect produced is called ‘Moment of force’.

Mathematically it can be expressed as the product of Force applied and the perpendicular distance of force from the fulcrum point.

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