Simple Machines

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Simple Machines

• Group MM

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PULLEY!
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Definition

• Pulley is a simple machine that involves a wheel,
  that holds a rope or line. It helps to spread out
  the weight to lessen the force needed and used so
  that more weight can be lifted

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Types of Pulleys

• FIXED PULLEY
• MOVABLE PULLEY
• COMBINED PULLEY

Fixed Pulley
Flat Pulley
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Mechanical Advantage

• The main advantage of a pulley
• (which was once said by
• Archimedes) is to lift heavier
• weight with less force.

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Story Time

• According to Plutarch, Archimedes had stated in
  a letter to King Hieron that he could move any
  weight with pulleys he boasted that given enough
  pulleys he could move the world! The king
  challenged him to move a large ship in his
  arsenal, a ship that would take many men and
  great labor to move to the sea. On the appointed
  day, the ship was loaded with many passengers and
  a full cargo, and all watched to see if
  Archimedes could do what he said. He sat a
  distance away from the ship, pulled on the cord
  in his hand by degrees, and drew the ship along
  "as smoothly and evenly as if she had been in the
  sea."
• http//www.swe.org/iac/lp/pulley_03.html

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Best Mechanical Advantage

• The Mechanical Advantage is a ratio. The higher
  the advantage the easier it is to lift the
  weight.
• Formula
• The easiest way to find mechanical advantage of
  a pulley is to count the number of ropes then
  subtract one. The reason you subtract one is
  because you never count the one you are pulling.
• ex.
• Say there are 7 ropes
• 7 1 (the one you are pulling) 6
• therefore the mechanical advantage is 6

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Compound Machine

• Levers
• Wheel and Axle
• Pulley

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• Screw
• Wheel and Axle
• Pulley

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• Screw
• Wheel and Axle
• Pulley

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Screw

• By Kimmy Gardyasz

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The Screw is

• The screw is an inclined plane wrapped around a
  shaft. This form of inclined is helical. It has a
  rounded head at the top, from which the screw can
  be rotated to be tightened or loosened.
• A screws function can include holding things
  together and raising/lowering things.

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Mechanical Advantage

• MADistance over which effort is
  applied/distances over what the load is moved is
  the basic equation basis for simple machines in
  general.
• To find the mechanical advantage of a screw you
  can take the pitch of the screw divided by its
  circumference.
• the pitch is the length of one screw thread (or
  end) to another.

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Finding mechanical advantage (example)

• Find the mechanical advantage of a screw that is
  5 cm in length (pitch) and a 2 cm circumference.
• 5/22.5 cm

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How a screw changes force?

• In comparison to the large amount of force used
  to overcome resistance force, the screw only uses
  a small force to turn.
• A screw can hold something together, keeping the
  force equal and together.
• Also a screw can lessen the force when something
  goes around down a screw.

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Pencil Sharpener

• Wedge
• Screw
• Wheel and Axle
• Lever

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Bicycle

• Screw
• Wheel and axle
• Lever
• pulley

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Wing-Handle Corkscrew

• Rack and pinion
• Wheel and axle
• Screw
• Lever

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• http//www.coe.uh.edu/archive/science/science_less
  ons/scienceles1/screw.htm
• http//www.uark.edu/depts/aeedhp/agscience/simpmac
  h.htm
• http//en.wikipedia.org/wiki/Screw
• http//www.ehow.com/how-does_4598341_what-simple-m
  achines-pencil-sharpener.html
• http//www.mos.org/sln/Leonardo/GadgetAnatomy.html
  

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Wheel Axle

• By Delaina Padillas

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Explanation

• A simple machine consisting of a large wheel
  securely attached to a smaller wheel, called an
  axle. When one turns, the other turns. A full
  rotation of a wheel equals a full rotation of an
  axle.

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Pictures!!
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Mechanical Advantage

• The advantage to using a wheel and axle is the
  ratio of the radius of the wheel to the radius of
  the axle.
• The relationship is demonstrated by these
  equations
• MA Distance moved by the wheel / distance moved
  by the axle
• MA Diameter of the Wheel / Diameter of the Axle

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Changes Force

• You can apply the input force to the axle rather
  than to the wheel to increase speed.

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Example

• The diameter of a wheel is 10 cm. The radius of
  the axle is 4 cm. (Remember radius is half of
  the diameter)
• MADiameter of the Wheel/Diameter of the Axle.
• MA10 cm/8 cm
• MA1.25 cm

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Compound Machine 1

• Wheelbarrow
• Uses lever and wheel axle

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Compound Machine 2

• Lighter
• Uses 2 Wheels and a Lever

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Compound Machine 3

• Bicycle
• A pulley, wheel axle, lever, and screws

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Annotated Bibliography

• http//www.uark.edu/depts/aeedhp/agscience/simpmac
  h.htm
• http//sceince.jrank.org/pages/4056/Machines-simpl
  e-wheel-axle.html
• http//www.sciencebyjones.com/simple_machines.htm
• http//education.jlab.org/jsat/powerpoint/0708_sim
  ple_machines_8.ppt301,22,Wheel and Axel
• http//en.wikipedia.org/wiki/Wheel_and_axle

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The Wedge- A Simple Machine

• Justine Lundsted

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What is a wedge?

• A triangular shaped tool
• One of the six classic simple machines
• A portable inclined plane
• Uses
• Separating two objects or parts of an object
• Lifting an object
• Holding an object in place

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Mechanical Advantage of a Wedge

• The mechanical advantage of a wedge can be found
  by dividing its length by its width.
• MAL/W
• The more narrow the angle of the wedge- the
  greater ratio of its length to its width, which
  gives it a better mechanical advantage (unless
  dealing with elastic material).

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Example

• The wedge you are using to chop wood is 12 inches
  long and 3 inches wide. What is the mechanical
  advantage of this wedge?
• MA L/W
• MA 12 in. / 3 in.
• MA 4 in.

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How Does the Wedge Change the Force?

• The wedge converts the force applied to its blunt
  end into forces perpendicular to its length (as
  seen in the picture to the left).

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Compound Machine 1(pencil sharpener)

• Contains a screw and wedge

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Compound Machine 2 (a bucket)

• Works with a wheel and axle, a pulley, and a
  wedge.

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Compound Machine 3(boom mower)

• Has a wheel and axle, pulley, and wedge.

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Bibliography

• http//en.wikipedia.org/wiki/Wedge_(mechanical_dev
  ice) (used for description)
• http//images.google.com/imgres?imgurlhttp//faba
  thome.org/machinesandmechanisms/images/ (used for
  pictures)
• http//z.about.com/d/homeschooling/1/0/8/Z/4/machi
  newedge.png
• http//www.uark.edu/depts/aeedhp/agscience/simpmac
  h.htm (used for mechanical advantage)
• http//teacher.scholastic.com/dirtrep/simple/wedge
  .htm

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Simple Machine Lever

• Sarah Peiffer

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How Does It Work?

• A lever operates with a fulcrum, or pivot point,
  which multiplies the force applied to an object
• A lever can be used to move a heavy force over a
  short distance by exerting a small force over a
  long distance
• There are 3 different kinds of levers

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First Class Lever

• A lever in which the fulcrum is located between
  the input force and the output force.
• Example Seesaw

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Second Class Lever

• The input force is on one end and the fulcrum is
  on the opposite end with the output force in
  between.
• Example Wheelbarrow

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Third Class Lever

• The output force is on one end opposite the
  fulcrum and the input force is in between.
• Example Tongs

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Mechanical Advantage

• Mechanical Advantage is the machines affect on
  the output force
• Mechanical Advantage Load / Effort
• If a force of 10 N is applied
  to a move a 100 N weight
  the MA is 10

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How the Force is Changed

• Work Force x Distance
• F1D1F2D2
• A force of 10 N can be applied over a distance of
  30 feet to move a 30 N force a distance of 10 feet

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Example

• A force of 20 N is applied to move a 200 N
  weight. What is the Mechanical Advantage?
• MA 200 N / 20 N
• MA 10

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Breakdown Trebuchet

• Type 1 Lever
• Wheel and Axel
• Screw

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Breakdown Wheelbarrow

• Type 2 Lever
• Wheel and Axel
• Screw

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Breakdown Stapler

• Type 3 Lever
• Modified Screw
• Wedge

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Bibliography

• http//www.math.nyu.edu/crorres/Archimedes/Lever/
  LeverLaw.html
• This is a site describing the history behind the
  lever.
• http//en.wikipedia.org/wiki/Lever
• This site defined lever and gave its equation. It
  also defined the 3 types if levers.
• http//www.uark.edu/depts/aeedhp/agscience/simpmac
  h.htm
• This site defines mechanical advantage and
  explains how it works.
• http//www.dynamicscience.com.au/tester/solutions/
  hydraulicus/simplemachineslevers4.htm
• http//library.thinkquest.org/J002079F/lever.htm

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The Incline A Simple Machine

• PowerPoint by
• Kiersha Keller

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What is an incline?

• An incline is a flat surface whos endpoints are
  at different heights.
• Rather than moving across the plane vertically,
  the force that you need to give is reduced.
• The trade-off is that an object must go more of a
  distance.

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Simple Inclines
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The Advantages of Using an Incline

• It reduces the force neccesery to move something
  across an area on a low angle.
• The trade off is that you must go a longer
  distance.
• However, the amount of work stays the same.

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Breaking it down

• When something is put on an incline, it will only
  move if the force of friction is a smaller amount
  then the combined force of both gravity and
  normal forces.
• When the angle of the incline is 90 the object
  will only free fall.
• The incline formula is the following
• IMA length/height

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How the Incline helps

• The incline helps by allowing gravity to do some
  of our work.
• When you tilt a surface in the downward direction
  (like an incline), the gravitational force beats
  out the friction.
• In this case, the incline helps to take away the
  friction so the surface slides across more easily.

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MA S/H
MA 18/3 6
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Wheelbarrow
Wheel Axel
Lever
Inclined Plane
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Escalator
Inclined Plane
Wheel Axel
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Incline Cable Car
Wheel Axel
Inclined Plane
Pulley
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Websites that I used

• http//en.wikipedia.org/wiki/Inclined_plane
• http//www.usoe.k12.ut.us/curr/Science/sciber00/8t
  h/machines/sciber/machines.htm
• http//www.mos.org/sln/Leonardo/InventorsToolbox.h
  tml

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2 more!

• http//www.edheads.org/activities/lesson_plans/pdf
  /sm_04.pdf
• http//library.thinkquest.org/CR0210120/Compound2
  0machine.html