Definition of PULLEY: A simple machine consisting essentially of a wheel with a grooved rim in which a pulled rope or chain can run to change the direction of the pull and thereby lift a load. A simple machine consisting essentially of a wheel with a grooved rim in which a pulled rope or chain can run to change the direction of the pull and thereby lift a load.
Resources en.wikipedia.org/wiki/Pulley en.wikipedia.org/wiki/Pulley library.thinkquest.org/27948/pulley. html library.thinkquest.org/27948/pulley. html library.thinkquest.org/J002079F/pull ey.htm library.thinkquest.org/J002079F/pull ey.htm www.howstuffworks.com/pulley.htm www.howstuffworks.com/pulley.htm www.coe.uh.edu/archive/science/sci ence_lessons/scienceles1/pulley.ht m www.coe.uh.edu/archive/science/sci ence_lessons/scienceles1/pulley.ht m
What is it? –An inclined plane is a flat surface whose endpoints are at different heights –A slanted surface that raises an object. –When an inclined plane is used, less force is needed than if an object would go straight up.
LEVERS A lever is a simple machine that makes work easier. A lever is a simple machine that makes work easier. Levers involve moving a load around a pivot using a force. Levers involve moving a load around a pivot using a force.
ORDERS/ CLASSES In a Type 1 Lever, the pivot (fulcrum) is between the effort and the load. In a Type 2 Lever, the load is between the pivot (fulcrum) and the effort. In a Type 3 Lever, the effort is between the pivot (fulcrum) and the load.
Mechanical Advantage The mechanical advantage of a lever is the ratio of the length of the lever on the applied force side of the fulcrum to the length of the lever on the resistance force side of the fulcrum. –Mechanical Advantage= Effort Arm/Resistance Arm
Example of Mechanical Advantage 10:1 Resistance Arm Resistance Arm Effort Arm Effort Arm
Compound machines Wheel Barrel: –Lever –Wheel and Axle
Compound machines Bicycle –Screws –Wheel and axle –Lever –Pulley
Bibliography http://www.uark.edu/depts/aeedhp/agscience/simpmach.ht m used this site for mechanical advantage http://www.enchantedlearning.com/physics.macnines/Levers. shtml used this site for classes and definition of a lever http://library.thinkquest.org/CR0210120/Compound%20mac hine.html used for compound machines http://www.technologystudent.com/forcmom/lever1.htm ^ used to find levels of levers http://library.thinkquest.org/J002079F/lever.htm ^found info on levers
Simple Machines The Screw Kati Myers Pd. 12 2/26/2009
What is a screw? A screw is actually an inclined plane that is wrapped around a cylinder and has a wedge at the tip. The incline plane is the thread that goes all the way around the screw. They are typically used to hold things together.
Mechanical Advantage and Equations Since there is a lot of friction the ideal mechanical advantage doesn’t mean much. But in order to lift heavy items or when needing to hold things together, the screw is of great advantage. Equation = Circumference -------------------- Pitch
Change in force A screw requires a small force when turning, in order to overcome a larger amount of resistance force.
Mechanical Advantage Problem For example, suppose a screw with 12 threads per inch is turned by a screwdriver having a handle with a diameter of 1 inch. The mechanical advantage would be calculated as follows: First, determine the pitch of the screw... Pitch = 1 = 1 =.083 12 threads/inch of screw 12 Second, determine the circumference of the handle of the screwdriver... Circumference = 3.14 x diameter = 3.14 x 1 = 3.14 inches Finally, insert the values obtained into the formula and solve the equation... Mechanical Advantage = Circumference = 3.14 inches = 37.83 Pitch.083
Links http://en.wikipedia.org/wiki/Screw_(simple_machine) Explained how my simple machine works. http://www.weirdrichard.com/screw.htm Allowed me to see how a screw can change forces. http://www.mikids.com/Smachines.htm Gave different examples of what a screw is. http://www.uark.edu/depts/aeedhp/agscience/simpmach.htm Helped out when I needed to make up my own mechanical advantage problem. http://science.jrank.org/pages/4058/Machines-Simple- Screws.html http://science.jrank.org/pages/4058/Machines-Simple- Screws.html Provided good information explaining what a screw is
What is a wedge and it’s advantage? The wedge is the active twin of an inclined plane The wedge is the active twin of an inclined plane This simple machine consists of a pair of inclined planes set face-to-face, that can sustain relative sliding or rolling motion. Which makes it an advantage for a controlled and precise motion This simple machine consists of a pair of inclined planes set face-to-face, that can sustain relative sliding or rolling motion. Which makes it an advantage for a controlled and precise motion
How does a wedge change the force? The purpose or advantage of the wedge is to change the direction of the applied force. When the force is applied downward on a wedge, it is able to push outward in two directions
Equation that shows mechanical advantage of a Wedge! MA= L / W To solve the equation to find the mechanical advantage of a wedge you have to take the ratio to its length to the ratio of its width
Example of Mechanical Advantage MA=L / W MA=L / W MA=12/4 MA=12/4 MA=3 MA=3
Compound Machine #1- Boat The wedge is located that the front of the boat, where the boat actually splits the water to let it glide. A pulley is also located in the boat which turns the wheels. Which makes a boat a compound machine.
Compound Machine #2- Fan The blades in which cut the air as it spins is acting as a wedge There is a wheel and axel in which makes the fan spin. Which considers it a compound machine
Compound Machine #3- Shovel The metal in which spits the ground as it shovels serves as the wedge The handle in which sticks out from the wedge serves as a lever which makes a shovel a compound machine
Websites Used http://www.weirdrichard.com/wedge.htm http://www.sciencetech.technomuses.ca/e nglish/schoolzone/Info_Simple_Machines2.c fmhttp://www.sciencetech.technomuses.ca/e nglish/schoolzone/Info_Simple_Machines2.c fm http://hyperphysics.phy- astr.gsu.edu/HBASE/Mechanics/incline.htmlhttp://hyperphysics.phy- astr.gsu.edu/HBASE/Mechanics/incline.html http://www.sasked.gov.sk.ca/docs/elemsci/ gr5uhttp://www.sasked.gov.sk.ca/docs/elemsci/ gr5u http://www.uark.edu/depts/aeedhp/agscien ce/simpmach.htmhttp://www.uark.edu/depts/aeedhp/agscien ce/simpmach.htm
What is it? Well, the simple machine “Wheel and Axle,” consists of a large wheel, attached to a smaller wheel. Then, you can turn the smaller wheel, making the big wheel cover more distance. Or, if you turn the big wheel, it takes less force, but requires more motion.
Mechanical Advantage The mechanical advantage of a wheel and axle is equal to the rotation of the radius of the wheel to the radius of an axle. The equation for the mechanical advantage is the ratio of the size of the wheel to the size of the axle.
Ideal Mechanical Advantage The wheel and axle changes the rate at which force is applied. If the force is applied to the axle, more force is required, but the distance traveled is greater. And vice – versa. M.A. = RadiusWheel/RadiusAxle As the small wheel turns, the big wheel turns at the same revolutions, but with the big wheel, that is a bigger distance. =]
Car The simple machines in a car are the wheel and axle, the levers, the pulleys, and probably more.
Fans! A fan is a complex machine that uses a wheel and axle. The axle is the small cylinder that comes down from the ceiling. The wheel are is made up of the blades Of the fan. It also uses a wedge to slice the air and pulleys in the motor.
Wheel Barrow! A wheel barrow is a complex machine that uses a wheel and axle. It also uses a lever when you lift the handle. The wheel then acts as a fulcrum.