Simple Machines

There are six simple machines. They are:

• Incline Plane
• Lever
• Pulley
• Wheel and Axle
• Wedge
• Screw

Each simple machine has been in use for thousands of years, and make it easier to do work.

Lever

• A simple machine consisting of a rigid bar that pivots around a fulcrum
• Allows a load to be moved using less effort by increasing the distance over which the effort is applied

$$ \text{IMA} = \frac{\text{Load distance to fulcrum}}{\text{Effort distance to fulcrum}} $$

Pulley

• A simple machine consisting of a wheel with a grooved rim and a rope or cable
• Allows a load to be lifted by changing the direction of the force and/or reducing the effort required

$$ \text{IMA} = \text{Number of supporting rope segments} $$

Wheel and Axle

• A simple machine consisting of a wheel attached to a smaller axle
• Allows a small effort force applied over a large distance to move a larger load

$$ \text{IMA} = \frac{\text{Radius of wheel}}{\text{Radius of axle}} $$

Inclined Plane

• A flat surface set at an angle to raise or lower a load
• Allows a load to be moved with less force by increasing the distance over which the effort is applied

$$ \text{IMA} = \frac{\text{Length of ramp}}{\text{Vertical height}} $$

Wedge

• A simple machine made of two inclined planes joined together
• Allows a force applied over a longer distance to split, cut, or separate materials

$$ \text{IMA} = \frac{\text{Length of wedge}}{\text{Thickness of wedge}} $$

Screw

• A simple machine that is an inclined plane wrapped around a cylinder
• Allows a small rotational effort to produce a large linear force

$$ \text{IMA} = \frac{\text{Circumference}}{\text{Pitch}} $$