By: John BreslinSarah Kravinsky

Zoe AdlerNeal Khaisman

Table of Contents

LeversScrewsInclined plainsPulleys WedgesWheels and Axel

Resources

A rigid bar that rotates around a fixed point The fixed point is a fulcrum IMA = distance from fulcrum to input

force÷ distance from fulcrum to

output 3 different types of levers- 1 class, 2 class,

3 class

What are levers?

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A screw is sometimes considered an inclined plane wrapped around a cylinder

The closer together the threads are, the greater the MA

Examples: bolts, screws, faucets, jar lids

What are screws?

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A pulley is a grooved wheel with a rope,chain, or steel cable wrapped around it.

A pulley is used by pulling on the rope, chain, or cable around it. A pulley makes work easier by changing the amount and

direction of your input force. Pulleys are used to lift large masses onto tall structures.

Did you know? Pulleys are also called blocks and sheaves. Did you know? Pulleys are also called blocks and sheaves.

What are pulleys?

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A flat, slanted surface Allows you to exert a force over a longer

distance Ideal mechanical advantage= length of

incline/ height of incline Example situation: A box is too heavy to lift

from one level to another. To increase the distance over which you are pulling it, you set up a ramp. It is now easier to pull the box up to the higher level.

What are inclined planes?

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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Wheels and axles, such as those on carts, reduce resisting force by distributing it throughout the wheel or axle, and therefore make it easier to haul loads.

The formula for finding the mechanical advantage of a wheel and axle is the ratio of the radius of the wheel to the radius of the axle.

Watch a video about wheels!

What are wheels and axels?

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A device that combines two or more simple machines.

To find out the ideal mechanical advantage of a compound machine, you must know the mechanical advantage of each simple machine.

Example: a mechanical pencil sharpener. When turning the handle, you are using a wheel and axel. The two wheels inside are screws that whittle away at the pencil, making it sharp.

What are compound machines?

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http://en.wikipedia.org/wiki/Pulley

http://library.thinkquest.org/27948/pulley.html

Science explorer science textbook

http://images.google.com/imgres?imgurl=http://encyclozine.com/Science/Physics/Machines/incline.gif&imgrefurl=http://encyclozine.com/Science/Physics/Machines/&h=197&w=316&sz=3&hl=en&start=8&um=1&tbnid=JdnWB-9PPRsgiM:&tbnh=73&tbnw=117&prev=/images%3Fq%3Dinclined%2Bplane%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN

Resources

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