Force and moments

The turning effect to accomplish a task is called the moment of a force.
The principle of moments state :When a body is in equilibrium, the sum of clockwise moments about the pivot is equal to the sum of anticlockwise momenra about the same pivot.
To calculate the moment of a force : M=F x D(perpendicular distance from the pivot to the line of action of the force.)
Note : work done is calculated by :F x Parallel distance
The S.I. unit of moments is Nm(Newton metre)

In the picture on the above,to calculate the effort needed,take the weight of the load and mulitply it with the distance from the load to the pivot then divide it by the distance of the pivot to the effort

In this second class lever above ,multiply the distance from the load to the pivot with the weight of the load .Divide the result with the distance between the load and effort.

For the third class lever,mutlitply yhe weight of the load and the distance o the load to the effort.Then,use the result and divide it by the distance of the effort to the pivot.