Physics 8463 - 4.5 Forces

A force or a system of forces may cause an object to rotate.

You should be able to describe examples in which forces cause rotation.

The turning effect of a force is called the moment of the force.

The size of the moment is defined by the equation:

moment of a force = force × distance from the turning point (or fulcrum)

M = Fd

This equation is NOT given on the Physics equation sheet - you need to know it, what the letters mean and are measured in!

M = moment of a force, in newton-metres, Nm

F = force, in newtons, N

d = distance, is the perpendicular distance from the pivot (fulcrum - turning point) to the line of action of the force, in metres, m

If an object is balanced, the total clockwise moment about a pivot equals the total anticlockwise moment about that pivot.

You should be able to calculate the size of a force, or its distance from a pivot, acting on an object that is balanced.

A simple lever and a simple gear system can both be used to transmit the rotational effects of forces.

You should be able to explain how levers and gears transmit the rotational effects of forces.