Six Simple Machines

Simple Machines

• Simple machines are the six machines on which all other machines are based.– Lever– Wheel & Axle– Pulley– Inclined Plane– Wedge– Screw

Lever• A solid bar that

rotates, or turns, around a fixed point. The bar can be straight or curved.

• The fixed point is called the fulcrum.

Levers

• AMSTI Demonstration

Wheel & Axle

• A Simple machine made of a wheel attached to a shaft, or axle.

• Effort applied to the wheel turns the axle, or effort applied to the axle turns the wheel. They move together.

• A wheel with a grooved rim and rope or cable that rides in the groove. As you pull on the rope, the wheel turns.

• Remember the Pulley lab from yesterday.

• Fixed and Movable Pulley’s

Inclined Plane

• It can be difficult to lift a heavy object straight up because it’s too heavy.

• Using a ramp or inclined plane makes work easier.

Wedge

• A simple machine that has a thick end and thin end. Wedges are used to cut, split, or pierce objects—or to hold objects together.

• It is a type of inclined plane.

Screw• An inclined plane wrapped around a cylinder or

cone to form a spiral.• Can be used to raise and lower weights as well

as to fasten objects. • The advantage of using a screw instead of a nail

to hold things together is friction keeps the screw from turning and becoming loose.

Mechanical Advantage

• The mechanical advantage of a machine can be calculated.

Mechanical = Output Force

Advantage Input Force

The formula works for ALL Machines!

Practice Problem

• If the output force of a machine is 600 N, and the input force is 200 N. What is the mechanical advantage of the machine?

• MA= Ouput

Input

MA= 600 N

200 N

MA= 3

Review Questions

1. What are the 6 types of simple machines and give an example of each.

2. How do you calculate mechanical advantage?