1. Work
Power
Machines
Simple Machines

2. http://player. discoveryeducation. com/index. cfm

3. Simple Machines
Ancient people invented simple machines that would help them overcome resistive forces and allow them to do the desired work against those forces.

4. WORK
Work is done on an object when the object moves in the same direction in which the force is exerted.
Work= Force x Distance

5. Power
The rate at which work is done
Power= Work
Time

6. A mechanical device that changes the direction or amount of force
Simple Machine pg.2
A mechanical device that changes the direction or amount of force
The simplest mechanisms that provides mechanical advantage

7. Machine pg 3
A device that allows you to do work in a way that is easier and more effective

8. The forces you exert on a machine
Input Forces PG 4
The forces you exert on a machine

9. The force the machine exerts on an object .
Output Forces pg 4
The force the machine exerts on an object .

10. Input force x Input distance
Work pg 4
Input Work
Input force x Input distance
Output Work
Output force x Output Distance

11. Mechanical Advantage pg 5
The number of times a machine increases a force exerted on it.
Mechanical Advantage Formula
Output Force
Input Force

12. Simple Machines Incline Plane Wedge Screw Lever Fulcrum Wheel and axle
Pulley

13. Inclined Plane pg. 6 A flat sloped surface. Ex. Ramp
Input force less than output force
Mechanical Advantage
Ideal mechanical advantage= Length of incline
Height of incline

14. Wedge pg. 8
A device that is thick at one end and tapers to a thin edge at the other end.
Ex. Ax blade
Zippers
Pencil Sharpener
Mechanical Advantage = Length of wedge
Width of wedge

15. When you bite into an apple your incisors act like wedges
Working Wedges
When you bite into an apple your incisors act like wedges

16. A rigid bar that is free to pivot, or rotate, on a fixed point.
Levers pg 10
A rigid bar that is free to pivot, or rotate, on a fixed point.
Fulcrum- The fixed point that a lever pivots around.

17. The body consist of levers of bones and muscles.
Living Levers
The body consist of levers of bones and muscles.
The joint acts as a fulcrum

18. Three Classes of Levers pg 10
1st Always change the direction of the input forces.
Ex. Paint Can Opener, scissors, and seesaws.

19. Three Classes of Levers pg 10
2nd Increase force but do not change the direction of the input force
Ex. Wheelbarrel
Doors
Bottle Openers

20. Three Classes of Levers pg 10
3rd Increase distance but do not change the direction of the input forces
Ex. Fishing Poles
Baseball Bats

21. Mechanical Advantage pg 11
Ideal Mechanical Advantage= Distance from fulcrum to input force Distance from fulcrum to output force

22. Screws pg 12
An inclined plane wrapped around a cylinder. This spiral inclined plane forms the threads of the screws.
Ex. Bolts
Light Bulbs
Jar lids
Mechanical Advantage = Length around the threads
Length of the screw

23. Wheel and Axle pg. 14
Made of two circular or cylinder objects fastened together that rotates about a common axle.
Largest radius called wheel
Smallest radius called axle
Ex. Screwdriver Handle wheel shaft is axle
Doorknob
Car Steering wheel

24. Ideal Mechanical Advantage pg 14
Radius of wheel Radius of axle Ex. Screwdriver wheel is 1.5 cm and the axle is .3 cm. What is the advantage

25. Made of a grooved wheel with a rope or cable
Pulleys pg 16
Made of a grooved wheel with a rope or cable

26. Types of Pulleys pg 16 Fixed Pulley
Does not change the amount of force applied.
It does change the direction of the force
Movable Pulley
Decreases the amount of input forces needed.
It does not change the direction of the force.
Block and Tackle
Combination of Fixed and Movable pulleys

27. Ideal mechanical Advantage pg 16
The number of sections of rope that support the object

28. A machine that utilize two or more simple machines
Compound Machines pg. 18
A machine that utilize two or more simple machines

29. Ideal Mechanical Advantage pg. 19
Product of the individual ideal mechanical advantage of the simple machines that make it up.