2. Types of Machines Levers Simple machine that has a bar that pivots at a fixed point This fixed point is called the fulcrum The load Input force 3 Types of levers

3. Types of Machines - Levers First class Fulcrum is between the input force and the load Always change the direction of the input force Used to increase force or to increase distance

4. Types of Machines - Levers Second Class The load is between the fulcrum and the input force Does not change the direction of the input force Allows you to apply less force than the force exerted by the load

5. Types of Machines - Levers Third Class Input force is between the fulcrum and the load Do not change direction of the input force Do not increase input force, meaning the output force is always less than the input force

6. Types of Machines - Guess d

7. Types of Machines

8. Types of Machines - Guess

9. Types of Machines

10. Types of Machines - Guess

11. Types of Machines

12. Types of Machines - Pulleys A simple machine that has a grooved wheel that holds a rope or a cable. A load is attached to one end of the rope, and an input force is applied to the other end

13. Types of Machines - Pulleys Fixed Pulley – attached to something that doesn’t move Pull down on rope to lift the load up Pulley changes the direction of the force Ex. Elevator

14. Types of Machines - Pulleys Movable Pulleys – Attached to the object being moved Does not change a force’s direction Increase force, but also increase the distance over which the input force must be exerted

15. Types of Machines - Pulleys Block and Tackles – When a fixed pulley and a movable pulley are used together Mechanical advantage of a block and tackles depends on the number of rope segments

16. Types of Machines – Wheel and Axle Consists of two circular objects of different sizes; the whell is the larger of the two circular objects Ex. Doorknobs, wrenches, and steering wheels

17. Types of Machines – Wheel and Axle Mechanical Advantage Found by dividing the radius of the wheel by the radius of the axle Turning the wheel results in a MA greater than 1 because the wheel of the radius of the wheel is larger than the radius of the axle

18. Types of Machines – Wheel and Axle

19. Types of Machines – Inclined Planes A straight, slanted surface Requires smaller input force than is needed to lift the piano into the truck Mechanical Advantage MA of an inclined plane can be calculated by dividing the length by the height to which the load is lifted

20. Types of Machines – Inclined Planes Wedges – made up of two inclined planes and that moves; often used for cutting Ex. Doorstops, chisels, scissors MA The longer and thinner the wedge is, the greater its MA Less input force is required Calculated by dividing the length of the wedge by its greatest thickness

21. Types of Machines – Inclined Planes Screws – consists of an inclined plane wrapped around a cylinder When turned, a small force is applied over the long distance along the inclined plane Screw applies a large force through the short distance it is pushed MA of Screws Longer the spiral on the screw and closer the threads/pitches are, the greater its MA

22. Types of Machines – Compound Machines Machine made up of more than one simple machine Ex. Block and tackle (two or more pulleys) Ex. Can opener (2 nd class lever, wheel and axle, and a wedge)

23. Types of Machines – Compound Machines Mechanical Efficiency Low in most compound machines Compound machines have more moving parts than simple machines do, thus, more friction to overcome

24. Types of Machines – Compound Machines Important to reduce friction Can damage the simple machines that make up the compound machine Use lubricants to reduce friction