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Simple Machines Group GG
Screw A screw is a simple machine that is made from another simple machine. It is actually an incline plane that wraps around itself, it has ridges and is not smooth like a nail. Screws are used to lower and raise things and they are also used to hold things together.
Mechanical Advantage • Circumference / pitch • Mechanical advantage of a screw can be found by dividing the circumference of the screw by the pitch
Example of mechanical advantage • Placing a ruler next to a screw and count 10 threads, the pitch of the screw would be 1/10
A sign……. A Screw is used in this picture.
a compound machine! And again, a screw is used.
Bibliography • http://www.manatee.k12.fl.us/sites/elementary/samoset/technology/Screw.htm ( Provided pictures of the simple machine at work in a compound machine) • http://www.edheads.org/activities/simple-machines/ (Showed all the simple machines and what they are used for) • http://www.mikids.com/Smachines.htm (Provided a definition of screw) • http://www.coe.uh.edu/archive/science/science_lessons/scienceles1/screw.htm • http://www.uark.edu/depts/aeedhp/agscience/simpmach.htm (found the mechanical advantage of a screw, and also found the example)
The Lever “Simple Machines” Erika Blauch
Lever • A lever is a simple machine that allows you to move a load around a pivot using a force • It is used to make work easier
A lever changes the force • A lever changes the force by allowing the user to shift the weight of the object by using the fulcrum. This makes the object easier to lift and move.
First Class Lever A first class lever is when the fulcrum is located in between the effort and the load.
Second Class Lever A second class lever is when the effort and load are located on the same end, while the fulcrum is located on the other.
Third Class Lever A third class lever is when the load is located on one end and the fulcrum on the other, while the effort is applied in between.
Equation to find the ideal mechanical advantage Amount of Effort MA= Resistance Effort *Use this if you are given the Amount of resistance and the amount of Effort Amount of resistance *Use this if you are given the distances from the load and effort to the fulcrum MA = Effort Arm Resistance Arm *Distances are measured from the load or effort to the fulcrum Effort Arm Resistance Arm
Problem • A man wants to lift a heavy rock by using a lever. • MA = Effort Arm Resistance Arm • 20m 10m Effort 20 m Resistance The mechanical advantage is 2 10 m
Compound machine (1st class) • A seesaw is a compound machine that contains the lever, screw, and the wheel and axle.
Compound machine (2nd Class) • A wheel barrow is a compound machine that contains the lever, and the wheel and axel.
Compound machine (3rd Class) • A construction crane is a compound machine that contains wheel and axle and a lever.
Bibliography • http://www.enchantedlearning.com/physics/machines/Levers.shtml • This site had the moving pictures for first, second, and third class levers. • www.bestinc.org/docs/Survival_Guide/education_resources/engineering_mechanics.pdf • www.imaginationfactory.questacon.edu.au/assets/im_levers.pdf • This site showed how the different types of classes work • http://www.edinformatics.com/math_science/simple_machines/lever.htm • http://www.tpub.com/content/engine/14037/css/14037_15.htm • This site had the mechanical advantage of the lever
Inclined Plane By Becky Guldin
According to Webster… An inclined plane is Main Entry: inclined plane Function: noun Date: 1710 : a plane surface that makes an oblique angle with the plane of the horizon
Mechanical Advantage • MechanicalAdvantage = Slope/Height
Inclined Plane • An inclined plane changes the force by allowing “one to overcome a large resistance by applying a relatively small force.”
Inclined Plane Example • What is the mechanical advantage of a plane with an incline of 15 feet and a height of 10 feet? • MA= slope/height • MA=15 ft / 10 ft • MA= 3/2 or 1.5
The Johnstown Incline • Inclined Plane • Pulley • Wheel and Axel • Screw
A Roller Coaster • Inclined Plane • Screw • Pulley • Wheel and Axel
Roller Slide • Inclined Plane • Wheel and Axel
Bibliography • http://www.merriam-webster.com/dictionary/inclined%20planeUsed to find a definition of “inclined plane” • http://74.125.47.132/search?q=cache:sYtg9veBsB8J:www.uark.edu/depts/aeedhp/agscience/simpmach.htm+mechanical+advantage+inclined+plane&hl=en&ct=clnk&cd=1&gl=usUsed for information on an incline’s mechanical advantage • http://www.weirdrichard.com/inclined.htmbUsed to find how an inclined plane changes force • http://images.google.com/images?hl=en&q=johnstown+incline&safe=active&um=1&ie=UTF-8&sa=N&tab=wiUsed for pictures of inclined plane • http://images.google.com/images?um=1&hl=en&safe=active&q=inclineUsed for pictures • **all five sources used
Wheel and Axle Simple Machines Project Dominic DiAngelis
Definition of a wheel and axle • a simple machine consisting, in its typical form, of a circular object that rotates on/around a smaller circular object. The outer object is known as the wheel, and the smaller inner object serves as the axle. The axle is placed in the center of the wheel in order for the two pieces to act with each other
How it works • Wheels help you move an object across a surface because they cut down on the amount of friction between what you're trying to move and the surface you're pulling it against. Though the entire circumference touches the ground at one point or another the weight is focused on the bottom most portion. Because only a small portion touches the ground the surface area is decreased, therefore also decreasing the amount of friction between the surface and the object.
Applications Wheels and axles are used generally in any situation where an object which would otherwise have too great of friction without the use of wheels to be moved. Wheel and axle applications. range anywhere from simple wagons to $300,000 Ferraris.
Mechanical Advantage • The mechanical advantage of a wheel and axle can be found by finding the ratio of the wheel’s radius to the axle’s radius. • MA = wheel’s radius ÷ axle’s radius
MA diagram • MA is = Wheel radius : axle radius • The MA of the wheel and axle in this diagram is 5:1 or 5
Ex. problem • If a Ferrari’s axle has a 2.5 in radius and the wheel/tire have a radius of 11in what is the mechanical advantage of the wheel/axle.
Answer to ex. problem • Because the wheel has a radius of 11in and the axle has a radius of 2.5in the MA is 4.4
Compound machines including wheel and axles. • A wheelbarrow uses three simple machines, a wheel and axle, lever, and inclined plane.
Compound machines cont. • This Lamborghini uses every single simple machine. Levers, pulleys, inclined planes, wheel and axle, wedges, and screws.
Assembly line rollers • These rollers use wheel and axles, inclined planes, and screws
Bibliography • http://www.edheads.org/activities/simple-machines/ examples and definitions of the simple machines • http://www.uark.edu/depts/aeedhp/agscience/simpmach.htm mechanical advantage of the simple machines • http://teacher.scholastic.com/dirtrep/simple/wheel.htm description of the wheel and axle • http://science.jrank.org/pages/4056/Machines-Simple-Wheel-axle.html description of the wheel and axle
Physics Project: Simple Machines Pulleys Alex Bailor
Pulleys • A pulley is simply a grooved wheel that rotates freely within a block of wood. • A pulley has a piece of rope attached to it. • A pulley changes the direction of force in order to gain a mechanical advantage. • A pulley can either be fixed or movable.
Fixed Pulleys • A fixedpulley does not move with the load being moved. • It changes a direction of force but it does not create a mechanical advantage.
Moveable Pulleys • A moveable pulley moves with the load that is being moved. • It creates a mechanical advantage but it does not change the force of direction.
Block and Tackle • A block and tackle uses both fixed and moveable pulleys. • It is able to create a mechanical advantage and change the direction of force.
Mechanical Advantage • The mechanical advantage of a pulley system is the number of ropes used to move it meaning every time the rope changes direction, count it as a new rope. • If the load is being pulled upwards, count all of the ropes. • If the load is being pulled downwards, subtract one from the total number of ropes.