1st Class Levers

 

This is the most common type of lever. With a class 1 lever the fulcrum is in the middle. The effort is on one side and the load is on the other. A see saw is an example of a class one lever. Other examples are a crowbar, scissors, claw hammer, tin snips, weight scales.

 

1st Class Example

 

 

The distance between the effort and the fulcrum, and also the load and the fulcrum governs the mechanical advantage and velocity ratio of the class 1 lever. If the load and effort are equal, and they are also both the same distance from the fulcrum, then the lever will be in balance (or equilibrium).

 

Equilibrium

 

If both load and effort are the same distance from the fulcrum, then if they are both of the same value, the system will be in balance. Increasing the effort will move the load. If the load is increased, then the effort must be increased by an equivalent amount.

 

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Levers are in equilibrium when the effort x distance of effort from fulcrum is equal to the load x distance of load from the fulcrum. So, if the load is only half the distance of the effort from the fulcrum, the effort needs only to be half of the value of the load.

 

If a load of 2Kg is 0.5m from the fulcrum and the effort is 1m from the fulcrum then the effort required is

2 x 0.5 / 1 = 1Kg

 

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