# Simple machines

Essay by Row BrownJunior High, 9th grade September 1996

Definitions:

Machine- A device that makes work easier by changing the speed , direction, or amount of a force.

Simple Machine- A device that performs work with only one movement. Simple machines include lever, wheel and axle, inclined plane, screw, and wedge.

Ideal Mechanical Advantage (IMA)- A machine in which work in equals work out; such a machine would be frictionless and a100% efficient

IMA= De/Dr

Actual Mechanical Advantage (AMA)- It is pretty much the opposite of IMA meaning it is not 100% efficient and it has friction.

AMA= Fr/Fe

Efficiency- The amount of work put into a machine compared to how much useful work is put out by the machine; always between 0% and 100%.

Friction- The force that resist motion between two surfaces that are touching each other.

What do we use machines for?

Machines are used for many things. Machines are used in everyday life just to make things easier.

You use many machines in a day that you might take for granted. For example a simple ordinary broom is a machine. It is a form of a lever. Our country or world would never be this evolved if it wasn't for machine. Almost every thing we do has a machine involved. We use machines to manufacture goods, for transportation, ect.

In the W=F*d equation the trade of between force and distance is as you use a machine the force goes down and distance goes up. If there was no friction they would be equal and trade.

There are six simple machines. They are a lever, pulleys, inclined plain, wheel and axle, screw, and wedge. The lever is used very often an example of a lever is a broom. Your hand is the fulcrum and when you sweep it is a lever. A lever consist of...