Simple Machines Simple machines are basic machines that

are the basis for all other forms of machines.

There are six types of simple machines: 1. Simple Lever 2. Pulley 3. Wheel and Axle 4. Inclined Plane 5. Wedge 6. Screw

Simple Machines Simple machines are divided into 2

families Lever Family

Simple Lever Pulley Wheel and Axle

Inclined Plane Family Simple Inclined Plane Wedge Screw

The Lever Family All levers have a rigid arm that turns

around a point called the fulcrum.

Levers are divided into three classes depending on the location of the fulcrum, input force, and output force.

First Class Levers The fulcrum is located between the

points of application of the input and output forces.

Example- Claw Hammer

Second Class Levers The fulcrum is at one end of the arm,

and the input force is applied at the other end.

Example- Wheelbarrow

Third Class Levers The fulcrum is located at one end of the

arm, and the output is found at the other end.

Example- Biceps

Pulleys Pulleys are levers. The middle of the

pulley is the fulcrum. The rest of the pulley acts like a first class lever.

Wheel and Axle The steering wheel of a car is a lever.

It’s made of a pulley (wheel) attached to a shaft (axle).

Inclined Plane Family Pushing an object up an inclined plane

requires less input force than lifting the same object does.

Pushing an object up a long gradual ramp requires less force than pushing up a short steep ramp.

Wedge A wedge turns a downward force into

two forces directed out to the sides. An ax blade or a wedge pushes through

and breaks apart the wood.

Screw A screw is an inclined plane wrapped

around a cylinder. Tightening a screw with threads requires

small force to act over a long distance.

Compound Machines A machine that uses more than one

simple machine. A pair of scissors uses 2 first class levers

joined at a fulcrum. Each arm has a wedge that cuts the paper.