Work and Machines

What is work?

Work is only done on an object when a force is applied to that object and the objecf moves over a distance

How is work calculated?

W= f x d

What is work measured in?

Joules, Newton-Meters

What is a machine?

A device that makes work easier

effort force

The force that you put into using a machine

resistance force

The force that the machine experts on the object

effort distance

The distance that you move the distance

resistance distance

The distance that the machine moves

What is work input?

The work that you do in using the machine

How is work input calculated?

Wi=FexDe

What is work output?

The work that the machine does on the object

How is work output calculated?

Wo= FrxDr

What is mechanical advantage?

The benefit of using a machine

Actual Mechanical Advantage (AMA)

A comparison of both forces

How to calculate AMA?

AMA= Fr/Fe

What is ideal mechanical advantage (IMA)

IMA is a comparison of both distances

How to calculate IMA?

IMA= De/Dr

What is efficiency?

Comparison of work input to work output

Is work input greater or less than work output?

Greater

What is the mathematical formula for efficiency?

Work output/Work input x100

What is a perfect machine?

A machine that has no friction, 100% efficient, work input= work output

What does the law of machines state?

No machine is 100% efficient

How can you reduce friction between parts of a machine?

Use lubricants, put on wheels

Pulley

a rope wrapped around a grooved wheel

fixed pulley

a pully which changes the diection of the effort

movable pulley

MĂșltiples The effort force

incline plane

Slanting surface connecting a lower level to higher level

wheel and axle

A lever that rotates in a circle around a rigid pole

Screw

An inclined plane wrapped around a central cylinder

Compound Machine

2 or more machines working together