Simple Machines

Machine

A tool that makes work easier.

Compound Machine

Two or more simple machines working together.

Geometric Plane

A flat surface that goes on forever in all directions.

Inclined Plane

A slanted surface (like a ramp) that makes lifting easier by reducing the force needed and increasing the distance.

Screw

An inclined plane wrapped around a rod (e.g. jar lid); used to hold, press tightly, lift, or move materials.

Wedge

A simple machine made of two inclined planes joined back to back, used to split, cut, push things apart, or hold things in place.

Lever

A bar that rotates around a fixed point called a fulcrum to lift or move a load using less effort.

Fulcrum

The fixed point a lever turns on.

First Class Lever

A lever where the fulcrum is between the load and effort (e.g. seesaw).

Second Class Lever

A lever where the load is between the fulcrum and effort (e.g. wheelbarrow).

Third Class Lever

A lever where the effort is between the fulcrum and load (e.g. tweezers, human arm).

Pulley

A simple machine consisting of a wheel with a groove and a rope or cord, used to lift heavy objects more easily by changing the direction of force.

Single Pulley System

A pulley system with one pulley; it changes direction but not force.

Double Pulley System

A pulley system with two pulleys; it reduces the force needed to lift a load.

Axle

A rod that a wheel turns around, forming part of a wheel and axle system.

Belt

A looped strip that transfers movement and power between wheels.

Drive Belt

A belt that connects a motor to a moving part to transfer power.

Conveyor Belt

A belt that moves objects from one place to another.

Gear

A toothed wheel that interlocks to turn other gears, used to increase speed, increase force, or change direction.

Gear Train

A group of gears working together.

Transmission

A system of gears that controls speed and power in a machine.

Driver (Gear)

The gear that starts the movement in a gear system.

Input Gear

The first gear that receives motion in a gear system.

Follower (Gear)

The gear that is turned by another gear.

Output Gear

The last gear in a system that performs the work or delivers output.

Idler Gear

A gear positioned between two others that changes direction but not speed.

Archimedes

A Greek mathematician and inventor (around 200 BC) known for studying simple machines and for inventions like the Archimedes screw and use of levers and pulleys.

Mechanical Advantage

The principle of making work easier with less force, often achieved using simple machines.

Wheel and Axle

A simple machine that reduces friction and makes it easier to move or lift objects, consisting of a larger wheel attached to a smaller axle.

What is the mechanical advantage formula for an inclined plane?

Mechanical advantage = length of ramp rac{\text{length of ramp}}{\text{height of ramp}}

What is the mechanical advantage formula for levers?

Mechanical advantage = distance from effort to fulcrum rac{\text{distance from effort to fulcrum}}{\text{distance from load to fulcrum}}

Why do people use machines?

People use machines to:

• Help move or lift things.
• Fix or build items.
• Make tasks easier and faster.