1. The Six Simple Machines

2. What is a Simple Machine?
Machines make work easier.
Six types of simple machines make work easier.
Machines can change the size, distance or direction of a force.
Six Simple Machines: Lever, Inclined Plane, Wedge, Screw, Wheel and Axle, and Pulley
Simple machines can be combined to make complex machines.

3. How Machines work Machines do not reduce the amount of work done.
Machines can be powered by different kinds of energy.
Machines can change either:
Direction of the force
Distance the force is applied
Size of the Force

4. Work Defined as a Force acting through a distance W = F * d
Measured in Joules (J)

5. Work Work is done only when Object moves, and
Object’s motion is in the direction of applied Force

6. Types of Mechanical forces
Two forces involved when machines are used to do work:
Input – force applied TO machine (Fin)
Output – force applied BY machine (Fout)
Work put INTO a machine should be greater than the work DONE by the machine

7. The Simple Machines These are divided into two families:
1- Lever Family & 2 - Inclined Plane Family

8. The Lever

9. Simple Machine – Lever Rigid Bar free to turn about a fulcrum
Three Parts: Resistance Force or Load, Effort Force, Fulcrum
Three Classes of Levers: First, Second, and Third

10. Simple Machine – First Class

11. Simple Machine – First Class
Fulcrum located between Resistance and Effort Forces
Resistance and Effort Forces are in opposite directions
Examples: Seesaw, Crowbars, Scissors, Claw Hammers

12. Simple Machine – Second Class

13. Simple Machine – Second Class
Resistance Force is between the Effort Force and the Fulcrum
Resistance and Effort Forces are in same direction
Examples: Wheelbarrow, Bottle openers, and Nutcrackers

14. Simple Machine – Third Class

15. Simple Machine – Third Class
Effort Force is between the Resistance Force and the fulcrum
Resistance and Effort Forces are in same direction
Examples: Broom, Shovel, Fishing Pole, Baseball Bat, and Tongs

16. The Inclined Plane

17. Simple Machine – Inclined Plane
Sloping surface allowing the lifting of heavy loads with less effort than directly lifting the load
Examples: Simple Ramp, Escalator, Stairs, Ship Plank, Ladder

18. The Wedge

19. Simple Machine - Wedge
Form of an Inclined Plane tapering to a sharp edge
Can be used to split, fasten, or cut
Examples: Ax Head, Screwdriver, Nails, Doorstop, Chisel, Plows

20. The Screw

21. Simple Machine - Screw
Form of an Inclined Plane wrapped in a spiral around a cylindrical post to fasten things
Two parts: Body and Thread
Examples: Drill Bits, Jackscrew, Fan Blades, Propellers, Screw, Nuts & Bolts

22. The Wheel and Axle

23. Simple Machine – Wheel and Axle
Wheel connected to a rigid pole
Modified Lever and center of axle serves as Fulcrum
Examples: Door Knobs, Handle Bars on Bike, Wheels on car, Roller Conveyor

24. Simple Machine – Wheel and Axle
Gears are modified forms of Wheel and Axle
Wheel has teeth along circumference
Effort Force exerted on larger gear to turn the smaller gear
Examples: Bike Sprockets, Can Opener, Machine Gears

25. The Pulley

26. Simple Machine - Pulley
Grooved wheel turning around a fulcrum to lift heavy objects
Rope or Chain used in groove
Can be fixed, movable, or combination of both
Examples: Flag Pole to raise Flag, Hoisting a Sail, Open Curtains or Mini Blinds,

27. Compound Machine
Compound machines are two or more simple machines working together.
A wheelbarrow is an example of a complex machine that uses a lever and a wheel and axle.

28. Mechanical Advantage
The benefit of doing work with a machine means less force is needed to do work The number of times a machine multiples the input force is called the machine’s MECHANICAL ADVANTAGE MA = Wout / Win x 100%

29. Mechanical Advantage
Machines that allow less force over greater distance (ramp) have a MA of greater than 1
Machines that allow more force over shorter distance (rake) have a MA of less than one
Machines that change the direction of the force (crowbar), but not the amount, have a MA of one