Forces and their effects GapFill

Forces can be categorised as contact or non-contact forces, depending on whether they require contact between bodies to act, or whether they act at a distance. Examples of contact forces include  air resistance, and electrostatic and gravitational forcesgravitational, electrostatic and magnetic forcesfriction, tension and weightfriction, air resistance and tension, and examples of non-contact forces include  friction, tension and weightair resistance, and electrostatic and gravitational forcesfriction, air resistance and tensiongravitational, electrostatic and magnetic forces.

If a force does not act through the centre of an object, it may cause a  magnetic effectrotationreflectioncrease in the object. The turning effect of a force is called a moment, which is given by the equation moment =  F²dFdFd²F/d, where F is the force exerted and d is the distance between the point where the force acts and the pivot, which is the centre of the rotation.
If the clockwise and anticlockwise moments on an object are equal, the object  is balancedrotates anticlockwiserotates clockwisemoves forwards.
A  levermomentpivotgear is a device used to transmit a rotational force. Often this is used to amplify the effect of a force, decreasing the force that needs to be exerted.
A  momentgearpivotlever is a rotating machine part, which changes the direction of a rotational force.