Simple Machines: lever, wedge, wheel and axle and pulley Group CC.

Simple Machines: lever, wedge, wheel and axle and pulley

Group CC

Lever y Wedge

Raquel y Victoria

C l a s s e s o f L e v e r s

“First Class Lever”A first-class lever is a lever in which the fulcrum is located between the input effort and the output load. In operation, a force is applied (by pulling or pushing) to a section of the bar, which causes the lever to swing about the fulcrum, overcoming the resistance force on the opposite side. The fulcrum may be at the center point of the lever as in a seesaw or at any point between the input and output. This supports the effort arm and the load.

Examples:

•Seesaw

•Scissors (double lever)


“Second Class Lever”

In a second class lever the input effort is located at the end of the bar and the fulcrum is located at the other end of the bar, opposite to the input, with the output load at a point between these two forces.

Examples:

•Paddle

•Wheelbarrow

•Wrench


For this class of levers, the input effort is higher than the output load, which is different from second-class levers and some first-class levers. However, the distance moved by the resistance (load) is greater than the distance moved by the effort. In third class levers, effort is applied between the output load on one end and the fulcrum on the opposite end.

“Third Class Lever” Examples:

•Hockey Stick

•Tweezers

•Fishing Rod

M e c h a n I c a l A d v a n t a g e

•First and Second class levers have a positive mechanical advantage.

•Third class levers have a mechanical disadvantage, meaning you use more force that the force of the load you lift.

Mechanical Advantage: Example

Mechanical Advantage= effort arm

resistance arm

Crazy Joe is moving bricks to build his cabin. With the use of his simple machine, a lever, he moves them easily. The “effort arm” of his wheel barrow is 4ft., while the resistance arm of his wheelbarrow is 1 ft.

4/1 is his mechanical advantage. MA= 4.

How Does it Change the Force?

“The length of the effort arm is the same number of times greater than the length of the resistance arm as the resistance to be overcome is greater than the effort you must apply.” Plugging these into an equation gives you the change in force by using a lever. whereL = length of effort arm,l = length of resistance arm,R = resistance weight or force, andE= effort force.

One convenience of machines is that you can determine in advance the forces required for their operation, as well as the

forces they will exert.

F o r c e C h a n g e

Suppose you want to pry up the lid of a paint can with a 6-inch file scraper, and you know that the average force holding the lid is 50 pounds. If the distance from the edge of the paint can to the edge of the cover is 1 inch, what force will you have to apply on the end of the file scraper?

L = 5 inchesl = 1 inchR = 50 pounds, andE is unknown. = 10 pounds

You will need to apply a force of only 10 pounds.

W h e r e c a n I f I n d t h e m?

Compound machine:Can Opener

Simple machines

- lever

-wheel and axel

-gear

-wedge


Compound Machine:Stapler

Simple Machines:-Lever-Wedge


Compound Machine:Wheelbarrow

Simple Machines:-Lever-Inclined Plane-Wheel and Axel

A n n o t a t e d B I b l I o g r a p h y

• http://en.wikipedia.org/wiki/LeverI got the three types of levers, examples and their functions. (used)

• http://www.tpub.com/machines/1c.htmI got the formula for mechanical advantage and example. (used)

• http://www.edheads.org/activities/simple-machines/frame_loader.htm

I found a list of compound machines and how simple machines were used in them. (used)

• http://www.coe.uh.edu/archive/science/science_lessons/scienceles1/lever.htm

I found examples of levers and how they work.

A n n o t a t e d B I b l I o g r a p h y

• http://www.science.jrank.org/pages/4060/Machines-Simple.htmlI used this site to find mechanical advantages, examples, and how a

basic lever works.

Simple MachinesSimple Machines

Levers y WedgesLevers y Wedges

Raquel y VictoriaRaquel y Victoria

W e d g e A wedge is “a piece of hard material with

two principal faces meeting in a sharply acute angle, for raising, holding, or splitting objects by applying a pounding or driving force, as from a hammer.” Wedges can be

used as either separating or holding devices.

Finding the Mechanical Finding the Mechanical AdvantageAdvantage

The mechanical The mechanical advantage of a advantage of a wedge can be wedge can be found by dividing found by dividing the length of either the length of either slope (S) by the slope (S) by the thickness (T) of the thickness (T) of the larger end (MA = larger end (MA = S/T).S/T).

For Example…

Assume that the length of the slope (S) of a wedge is 12 inches and the thickness (T) is 3 inches.

MA = S/T MA = 12 inches/3 inches MA = 4

How Does a Wedge Change the Force?

Wedges change the direction of an applied force.

When force is applied downward on a wedge, it distributes the force outward in two directions, separating a material.

A Wedge in a Compound Machine: Stapler

Staples are wedges: they cut through paper because their ends are pointed in a wedge shape.

Simple machines in a stapler: Wedge Lever

A Wedge in a Compound Machine: Can Opener

The cutting edge of a can opener cuts through metal because it is shaped like a wedge.

Simple machines in a can opener: Wedge Lever Gear Wheel and axle

A Wedge in a Compound A Wedge in a Compound Machine: ScissorsMachine: Scissors

► The cutting edge of The cutting edge of scissors is a wedge.scissors is a wedge.

► Simple machines in Simple machines in a pair of scissors:a pair of scissors: WedgeWedge LeverLever

Bibliography http://dictionary.reference.com/browse/

wedge http://www.uark.edu/depts/aeedhp/ags

cience/simpmach.htm http://

www.sciencetech.technomuses.ca/english/schoolzone/Info_Simple_Machines2.cfm

http://www.edheads.org/activities/simple-machines/frame_loader.htm

http://www.teachervision.fen.com/machines/printable/45019.html

By:Shawni Yeagley

Period:#1

(Wheel and Axle)

Wheel and axle is an example of a simple machine, that has two parts two it.

Unlike most simple machines, the parts have to work together, in order to move it.

Wheel and axle machines, has the axle attached to the wheel, to help it to move, and to speed up things.

pencil

sharpene

r1

Casters2

door knobs

3

rolling pIn4

rotary dial telephone

5

egg beate

r6

Bicycle7

Fan8

Windmill9

roller skate

s 10

record player

11

Wagon12

Well that uses the wheel and axle method.

A skate board is an example of a simple machine that uses the wheel and axle method.

It is a simple machine that consists of two circular objects, the wheel and the axle.

The axle is placed into the center or middle of the wheel, so that way it reduces the force that is needed to be applied, in order to move it.

It makes work easier by changing the amount on direction of the force applied to move the object.

The object that is being moved is a resistance(load) and the force applied to the outer edge of the wheel, is located at the axle.

Wheel and axle is a simple machine that is used to help move things, and the wheel and axle have to work together.

In order to use this machine, you need to have a force applied to either the axle or the wheel.

When the force is applied to the wheel, then the force is increased, the distance and speed are decreased.

when the force is applied to the axle, the force is decreased, the distance and speed are increased.

Wheel and axle makes work easier by changing the amount of force applied to the load.

Work is equaled to the amount of force applied to an object multiplied by the distance over which the force is applied, or in mathematical equation: work=force x distance.

The Mechanical Advantage of a Wheel and Axle measures how much the machine multiplies the force applied by the user. There are two kinds of mechanical advantages, ideal and actual.

The mechanical advantage equation is: MA=radius of the wheel divided by the radius of the axle.

The mechanical advantage Efficiency =work output divided by work input times 100%, or in other words; Efficiency= actual MA/Ideal MA x100%

Ideal Mechanical Advantages

◦ Its the mechanical advantage of an ideal machine. It is usually calculated using physics principles because we have no ideal machine. It is also known as the theoretical mechanical advantages or IMA.

◦ IMA = DE / DR, where DE equals the effort distance and DR equals the resistance distance, is the formula used to find the ideal mechanical advantage of a machine .

Actual Mechanical Advantages

◦ Its the mechanical advantage of a real machine. Actual mechanical advantage, or AMA, takes into consideration real world factors such as energy lost in friction, because of this way, it differs from the ideal mechanical advantage, to the efficiency.

◦ AMA = R / Eactual, Where, R is the resistance force, Eactual is the actual effort force, is the formula that you would used to calculate the actual mechanical advantage of a machine.

Mechanical advantages of wheel and axle is the ratio of the radius of the wheel, to the radius of the axle.

Here is an example of what I am talking about…

Eel

axle

wheel

1in 5in

The radius of the wheel is 5 times larger than the radius of the axle

The mechanical advantage is-5:1 or 5.

Note:The radius is equal to ½ the diameter of a circle

The way that using the Wheel and Axle method changes the force, is depending on how big the wheel is compared to the axle.

The smaller the wheel is, it gives you more speed, then what a bigger wheel would, because the bigger the wheel is, the further apart the force is around the wheel.

When applying a force to a wheel and axle machine, make sure that the wheel is big enough for the force, so that way the axle will not snap, from to much force.

A wheel Barrel is 1 example of a compound Machine, because it uses the wheel and axle simple machine and it uses the lever simple machine.

A manual can opener is another example of a compound machine because it uses three simple machines in it like the wheel and axle, which are the two wheels that rotate the lids, the two long arms that clamp the can securely make a simple machine called the lever, and the circular wheel that is sharpened, to cut the can lid is an example of a simple machine called a wedge.

A Car uses the wheel and axle method for the steering wheel and the axle, or other wise known as the Dry Shift. It also uses lever for things like the gas/brake pedals, and emergency brake. Screws are found anywhere in the interior and the hood, and car also have pulleys in the engine drive belt, for the water pump, and the alternator.

http://www.edinformatics.com/math_science/simple_machines/mechanical_advantage.htm

http://www.uark.edu/depts/aeedhp/agscience/simpmach.htm

http://www.mikids.com/Smachines.htm

http://images.google.com/images?hl=en&q=simple%20machines%20wheel%20and%20axle&um=1&ie=UTF-8&sa=N&tab=wi

www.georgiactae.org/Curriculum%20-%20Unit%20Plans/Engineering/.../STEM%20Mini-Golf%20Course/Simple%20Machines.ppt

http://www.teachengineering.org/view_lesson.php?url=http://www.teachengineering.org/collection/cub_/lessons/cub_simp_machines/cub_simp_machines_lesson03.xml

http://www.beaconlearningcenter.com/WebLessons/SimpleMachines/graphics/WandALabeled3.jpg

I used all the websites that are listed here….

PulleysPulleys

By:By:

Nate YavoichNate Yavoich

DefinitionDefinition

PulleyPulley• A simple machine made up of a wheel A simple machine made up of a wheel

and a cable.and a cable.• Used to lift up heavy objects.Used to lift up heavy objects.

How It WorksHow It Works

Pulleys consist of a wheel and a rope. One Pulleys consist of a wheel and a rope. One end of the rope is attached to an object end of the rope is attached to an object being lifted. The other end is what the being lifted. The other end is what the person using the pulley pulls on. The idea person using the pulley pulls on. The idea of the simple machine is to redirect the of the simple machine is to redirect the force required to lift the object so that the force required to lift the object so that the task becomes easier.task becomes easier.

Pulleys change the direction of the forcePulleys change the direction of the force

Mechanical AdvantageMechanical Advantage

Mechanical Advantage is the same as Mechanical Advantage is the same as the number of ropes supporting the the number of ropes supporting the objectobject

MA=2 MA=2 MA=4MA=2 MA=2 MA=4

ExampleExample

A box is lifted by two supporting A box is lifted by two supporting ropes. What is the mechanical ropes. What is the mechanical advantage?advantage?

MA=number of supporting ropesMA=number of supporting ropes

MA=2MA=2

Compound Machine #1Compound Machine #1

Bowflex: Pulley lifts the weight, the Bowflex: Pulley lifts the weight, the seat is an inclined plane, and the seat is an inclined plane, and the lever is what you pull to adjust the lever is what you pull to adjust the seatseat


Crane: The lever is the horizontal Crane: The lever is the horizontal beam that lifts the object, the pulley beam that lifts the object, the pulley is used to make the rope tight so that is used to make the rope tight so that it is easier for the crane to lift the it is easier for the crane to lift the objectobject


Ski Lift: It is an inclined plane to Ski Lift: It is an inclined plane to travel up a mountain. The pulley is travel up a mountain. The pulley is used to pull the ski lift to the top of used to pull the ski lift to the top of the mountainthe mountain

BibliographyBibliography

http://library.thinkquest.org/27948/pulley.hhttp://library.thinkquest.org/27948/pulley.htmltml • This site explains the use of the pulley system. This site explains the use of the pulley system.

Also provides an equation to figure out the Also provides an equation to figure out the force needed to lift an object with the pulley.force needed to lift an object with the pulley.

**http://library.thinkquest.org/J002079F/pullehttp://library.thinkquest.org/J002079F/pulley.htmy.htm • This site defines a pulley and explains how it This site defines a pulley and explains how it

makes lifting easier. This site also shows simple makes lifting easier. This site also shows simple examples of pulleys.examples of pulleys.

Bibliography (Cont.)Bibliography (Cont.)

**http://http://en.wikipedia.orgen.wikipedia.org/wiki/Pulley/wiki/Pulley• This site gave the definition of a pulley, different types of This site gave the definition of a pulley, different types of

pulley systems, and explains how these systems work.pulley systems, and explains how these systems work.

http://www.swe.org/iac/lp/pulley_03.htmlhttp://www.swe.org/iac/lp/pulley_03.html • This site gives a detailed explanation about pulleys. It This site gives a detailed explanation about pulleys. It

shows how it was invented, by whom it was invented, shows how it was invented, by whom it was invented, and provides pictures to show how a pulley works.and provides pictures to show how a pulley works.

**http://library.thinkquest.org/CR0210120/Mhttp://library.thinkquest.org/CR0210120/MA%20of%20PS.htmlA%20of%20PS.html • This site showed how to get the mechanical advantage This site showed how to get the mechanical advantage

for a pulley.for a pulley.

Simple Machines: lever, wedge, wheel and axle and pulley Group CC.

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