Key words: Simple machines, Class 1, Class 2, lever, force mechanical advantage, fulcrum, effort, load, weight, physical science, Ron Kurtus, School for Champions. Copyright © Restrictions

# Increasing Force with a Lever

by Ron Kurtus (20 November 2014)

You can use a Class 1 or Class 2 lever to increase the force pushing on the load, according to where the fulcrum is located. To increase the force on the load, the length of the effort arm of the lever must be greater than the length of the load arm.

The equation for the forces relates to the force mechanical advantage of the lever. From the equation, you can determine an unknown force or length.

Questions you may have include:

• What do the Class 1 and Class 2 levers look like?
• What is the lever force equation?
• What is an example of an application of the equation?

This lesson will answer those questions. Useful tool: Units Conversion

## Using Class 1 or Class 2 lever

You can use a lever to increase the applied force in order to lift a heavy load.

Lift heavy load with Class 1 lever

An application is using a Class 1 lever to lift a large rock.

Lift heavy load with Class 2 lever

A wheelbarrow is an example of using a Class 2 lever to lift and transport a heavy load. With a wheelbarrow, the wheel acts as the fulcrum.

## Lever force equation

The relationship between the effort and force on the load is dependent on the ratio of the arms of the lever, according to the equation:

FL/FE= dE/dL

or

FLdL= FEdE

where

• FL is the force on the load (can also be the weight lifted)
• FE is the effort force
• dEis the length of the effort arm
• dLis the length of the load arm

Note: FL/FE is also the force mechanical advantage of the lever.

## Application

How much effort is required to lift a load of 20 kilograms when the effort arm is 10 meters and the load arm is 1 meter?

Start by solving FLdL= FEdE for FE:

FE = FLdL/dE

Substitute in values:

FL = 20 kg

dL = 0.5 m

dE = 2 m

FE= 20*(0.5)/2 = 5 kg push required to lift the 20 kg weight.

## Summary

You can use a Class 1 or Class 2 lever to increase the force pushing on the load, according to where the fulcrum is located. To increase the force on the load, the length of the effort arm of the lever must be greater than the length of the load arm.

The equation for the forces relates to the force mechanical advantage of the lever. From the equation, you can determine an unknown force or length.

Set a goal to do your best

## Resources and references

Ron Kurtus' Credentials

### Websites

Machines Resources

### Books

Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible.

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www.school-for-champions.com/machines/levers_increase_force.htm

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