1. What is work ?
The product of the force applied to an object and the distance through which that force is applied.
Work = Force (N) x Distance (m)
1 N*m = Joule (J)

2. Is work being done or not?
Mowing the lawn
Weight-lifting
Moving furniture up a flight of stairs
Pushing against a locked door
Swinging a golf club
YES NO

3. Do you do more work when you finish a job quickly?
Work does NOT involve time, only force and distance.
No work is done when you stand in place holding an object.
Would you do more work if you ran up the stairs and skipped 2 at a time?

4. Power– rate at which work is done *work done in amount of time Energy:
Definitions:
Power– rate at which work is done
*work done in amount of time
Energy:
Ability to do work
Force x Distance
Work=
Force:
A Push or a Pull
Input force—force you exert
Output force–weight of the load

5. The 6 Simple Machines—allow you to do work in an easier way
Screw
Wedge
Inclined Plane
Pulley
Wheel and Axle
Lever

6. Inclined Plane
A sloping surface, such as a ramp. An inclined plane can be used to alter the effort and distance involved in doing work, such as lifting loads. The trade-off is that an object must be moved a longer distance than if it was lifted straight up, but less force is needed. You can use this machine to move an object to a lower or higher place.  Inclined planes make the work of moving things easier.  You would need less energy and force to move objects with an inclined plane. 

7. Inclined Planes
An inclined plane is a flat surface that is higher on one end (sloping)
Inclined planes make the work of moving things easier
A ramp allows you to exert less input force and energy but increases the distance
A sloping surface, such as a ramp. An inclined plane can be used to alter the effort and distance involved in doing work, such as lifting loads. The trade-off is that an object must be moved a longer distance than if it was lifted straight up, but less force is needed. You can use this machine to move an object to a lower or higher place.  Inclined planes make the work of moving things easier.  You would need less energy and force to move objects with an inclined plane. 

8. Inclined Plane
The Egyptians used simple machines to build the pyramids. One method was to build a very long incline out of dirt that rose upward to the top of the pyramid very gently. The blocks of stone were placed on large logs (another type of simple machine - the wheel and axle) and pushed slowly up the long, gentle inclined plane to the top of the pyramid.

9. The Screw An inclined plane wrapped around a cylinder.
The closer the threads, the greater the mechanical advantage
Examples: bolts, augers, drill bits

10. Screw
When you twist a screw, you exert an input force on the screw. The threads of the screw act like an inclined plane to increase the distance over which you exert the input force.

11. Wedges Two inclined planes joined back to back.
Wedges are used to split things.
Instead of moving an object along the inclined plane, you move the inclined plane itself

12. LEVERS
The position of the fulcrum identifies what kind of lever.

13. First-Class Lever
The fulcrum of a first-class lever is ALWAYS located between the input force (effort) and the output force (resistance)

14. **First Class Lever—change the direction of the input force.
Common examples of first-class levers include crowbars, scissors, pliers, and seesaws.

15. First Class Lever
Fulcrum- between Effort (Input force) & load (output force). If the fulcrum is closer to the output force, it will increase the force. Video: Science Trek—Simple machines 11:11

16. Second-Class Levers
Output force is located BETWEEN the input force and the fulcrum

17. ***Second Class Lever-increase force
Examples of second-class levers include nut crackers, wheel barrows, doors, and bottle openers.

18. Second Class Lever
The load (or output force) is between the fulcrum and the effort (or input force).

19. Third-Class Levers
Input force (or effort) is located between the fulcrum and the
output force (or load)

20. ***Third Class Lever— increase distance
Examples of third-class levers include tweezers, arm and shovels.
The effort is between the load and the fulcrum

21. Levers

22. Wheel and Axle
The wheel and axle is a simple machine consisting of a large wheel rigidly secured to a smaller wheel or shaft, called an axle.
When either the wheel or axle turns, the other part also turns. One full revolution of either part causes one full revolution of the other part.

23. WHEEL AND AXLE
EX. Ceiling fan--The axle is stuck rigidly to a large wheel. Fan blades are attached to the wheel. When the axle turns, the fan blades spin.
Ex. Screwdriver– handle is the wheel and the shaft is the axle

24. Pulleys- are wheels and axles with a groove around the outside
A pulley needs a rope, chain or belt around the groove to make it do work
Can either change the direction or the amount of effort force
Ex. Flag pole, blinds, stage curtain

25. Diagrams of Pulleys Fixed pulley: Movable Pulley:
A fixed pulley changes the direction of a force; however, it does not increase the force.
Movable Pulley:
Decreases the amount of input force needed but does not change the direction of the force

26. COMBINED PULLEY
The effort needed to lift the load is less than half the weight of the load and it changes the direction.
The main disadvantage is it travels a longer distance. 

27. Complex Machines A combination of two or more simple machines.
EX. Rube Goldberg machine
Cannot get more work out of a compound machine than is put in
Scissors are a good example. The edge of the blades are wedges. But the blades are combined with a lever to make the two blades come together to cut.
A lawnmower combines wedges (the blades) with a wheel and axle that spins the blades in a circle. But there is even more. The engine probably works in combination of several simple machines and the handle that you use to push the lawnmower around the yard is a form of a lever.

28. Rube Goldberg Machines
Rube Goldberg machines are examples of complex machines.
All complex machines are made up of combinations of simple machines.
Rube Goldberg machines are usually a complicated combination of simple machines.
By studying the components of Rube Goldberg machines, we learn more about simple machines

29. Safety Device for Walking on Icy Pavements
When you slip on ice, your foot kicks paddle (A),
lowering finger (B), snapping turtle (C) extends neck
to bite finger, opening ice tongs (D) and dropping pillow (E),
thus allowing you to fall on something soft.

30. Rube Goldberg Machine

31. The closer the fulcrum is to the object being lifted, the higher the person can lift the object. The longer the lever, the higher the object can be lifted.
Levers are all around us. Some examples of levers are: door handles, the claws of a hammer (for removing nails), crowbars, light switches, bottle openers and hinges.