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Wedge

Wheel and Axle. Lever. Simple Machines. Pulley. Screw. Wedge. Inclined Plane. Why are they Useful?. Simple machines are useful because they can make a physical job easier by changing the amount or the direction of the force exerted to do work. . Machine – a tool that helps us do work.

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Wedge

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  1. Wheel and Axle Lever Simple Machines Pulley Screw Wedge Inclined Plane

  2. Why are they Useful? Simple machines are useful because they can make a physical job easier by changing the amountor the direction of the force exerted to do work.

  3. Machine – a tool that helps us do work Machines help us by: • Changing the amount of force on an object. • Changing the direction of the force.

  4. Force is a push or pull. Example: I push a bookshelf to move it.

  5. Energy is the ability to do work. Example: I must have energy to run the mile.

  6. Work is the result of force moving an object. Example – Picking up something heavy is hard work!

  7. Load • the weight that is moved, lifted, or supported by a simple machine. Load

  8. Inclined Planes

  9. Inclined Plan – a slanted surface to make lifting easier Examples: ramp, stairs

  10. What is an Inclined Plane? • A ramp is an inclined plane. • A ramp helps move objects from one level to another - - higher or lower.

  11. An Inclined Plane is a simple machine that helps reduce the effort needed to move a load. Instead of picking up this load and lifting it straight upwards, the load can be pushed along an elevated plane. The user must move the load a greater distance, but the effort needed to move it will be less.

  12. Pulleys

  13. What is a Pulley? • A pulley is a simple machine with a wheeland a rope. • The rope fits around the edge of the wheel. • You can use a pulley to move a load up, down or sideways.

  14. A pulley is made of rope or string wound around a wheel to change the direction of a force.

  15. Examples of where pulleys can be used: • Flag Poles • Sailboat • Blinds • Crane • Curtains • Fishing Pole

  16. Pulley – a simple machine consisting of a wheel with a groove for a rope. • Fixedpulley is anchored to a single spot. It can rotate but does not move up or down. • Moveablepulley is free to move up and down. • Pulley systemis a group of two or more pulleys that work together to lift a load.

  17. The pulley does not move Single Fixed Pulley This pulley lets the user change the direction of the force, allowing someone to pull downto lift the load up. The effort needed to lift this load is equal to the weight of the load. This is because the load is supported by only 1 rope arm. You must also pull an amount of rope equal to the height you wish to lift the load

  18. Single Moveable Pulley The pulley moves This pulley system requires only halfthe effort needed to lift the weight of the load. If the load weighs 20 lbs, only 10 lbs of effort is needed to lift it. The load is supported by 2 rope arms under the pulley. Each load arm supports half the weight of the load, so the arm pulling up uses only 10 lbs of effort to lift this load. You must pull twice as much rope as desired to lift the load a certain height. Example: Pull 2 ft of rope for each 1 foot of height that you want to lift the load.

  19. Single Fixed/Single Moveable Pulley This pulley system combines the properties of their single components into a system that changes both the direction of the force and the amount of force needed to lift the load.

  20. 4 3 2 3 3 1 2 1 1 1 2 More supporting ropes = less force required to lift an object

  21. 4 3 2 3 3 1 2 1 1 1 2 Supporting rope arms only pull up, not down.

  22. Lever –made of a board or bar set on top of a fulcrum. It is used to lift weight Example: seesaw, crowbar, baseball bat, rake

  23. Simple Machines allow users to accomplish work more easily!

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