2Table of Contents Levers Three Classes of Levers Wheel and Axle Inclined PlaneWedgeScrewPulleyMore on PulleysWorks Sited
3LeverHow it works: A free bar that is free to move around a fixed point. The fixed point the ball rotates around is the fulcrum.Mechanical Advantage: Divide that input arm by the output arm
4Three Classes of Levers First-Class Lever- used to open paint cans the fulcrum is the inside edge of the paint canSecond-Class Lever- the output force is located between the input force and the fulcrumThird-Class Lever- the input force is located between the output force and the fulcrumThese classes are based on thelocations of the input force, theoutput force, and the fulcrum.2nd Class Lever1st class Lever3rd Class Lever
5Wheel and AxleHow it works: A simple machine that consists of two disks or cylinders that, each one with a different radius.Mechanical Advantage: Divide that radius where the input force is exerted by the radius where the output force is exerted. Can have a mechanical advantage of one or less than one.Example: A steering wheel
6Inclined PlaneHow it Works: A slanted surface along which a force moves an object to a different elevation.Mechanical Advantage: The distance along the inclined plane divided by its change in height.Example: The ramp that makes it easier to lift a refrigerator easier to lift into a truck.
7WedgeHow it Works: A V-shaped object whose sides are two inclined planes sloped toward each other.Mechanical Advantage: A thin wedge of a given length has a greater mechanical advantage than a thick wedge of the same length.Example: A sledgehammer that splits wood apart
8ScrewHow it works: An inclined plane wrapped around a cylinder. For two screws of the same length, the one whose threads are closer together moves foreword less for each turn of the screw.Mechanical Advantage: Screws that are closer together have a greater ideal mechanical advantage.Example: Nuts and bolts
9PulleyHow it works: A simple machine that consists of a rope that fits into a groove in a wheel. They produce an output force that is different in size, direction, or both, from that of the input force.Mechanical Advantage: Equal to the number of rope sections supporting the load being lifted.Example: Moving largefabricated parts in factories.
10More About Pulleys Fixed Pulleys: Pulley System: * A fixed wheel attached in a fixed location.* Only able to rotate in one place* The direction of the exerted force is changed by a fixed pulley, then the rope lifts the load up as far as you pull down the ropeMoveable Pulleys:* Attached to the object being moved rather than to a fixed location.* If you are pulling on the rope on the right with a force of 10 N, the both sides of the rope pull up with the same force of 10 N.Pulley System:* Combining fixed a moveable pulleys into a pulley system, a large mechanical advantage can be achieved* Consists of four segments of supporting rope, ignoring friction all four segments supply a lifting force as strong as the force you exert on the rope. Making the output four times greater than the input force.
11Compound MachineHow it works: A combination of two or more simple machines that operate together. The output force on one simple machine becomes the input force for another machine.Mechanical Advantage: The sum of all the mechanical advantages of all the simple machinesExample: ClockInside of a clock