1. Simple Machines The six simple machines are: Lever Wheel and Axle
Pulley
Inclined Plane
Wedge
Screw
Video

2. Simple Machines
A machine is a device that helps make work easier to perform by:
transferring a force from one place to another,
changing the direction of a force,
increasing the magnitude of a force, or
increasing the distance or speed of a force.

3. The Lever
A lever is rigid bar that is free to move about a fixed point.
In use, a lever has both an effort (or applied) force and a load (resistant force).
3 parts of lever:
Fulcrum (the fixed point)
Input arm (the side of the lever you exert a force on)
Output arm (the side of the lever that is doing the job)

5. Fulcrum is located in the middle. Ex: scissors

6. Load is between the fulcrum and the effort
Load is between the fulcrum and the effort. **Used to lift heavy loads by using a much greater input arm. Ex: wheel barrow, can opener, hammer

7. Effort is between the fulcrum and load
Effort is between the fulcrum and load. Ex: human forearm, stapler, tweezers

8. Wheel and Axle
Consists of a large wheel rigidly secured to a smaller wheel or shaft, called an axle.

9. Pulley A rope that fits into a grove in a wheel Three types:
Fixed- stationary (doesn’t move when you pull the rope)
Movable – moves with the lifted object
Pulley system- uses a combination of pulleys

10. Inclined Plane
An inclined plane is an even sloping surface. The inclined plane makes it easier to move a weight from a lower to higher elevation.

11. Although it takes less force for car A to get to the top of the ramp, all the cars do the same amount of work.
A B C

12. Wedge
V shaped- 2 inclined plane
Ex: ax

13. Screw
An inclined plan wrapped around a cylinder

14. MA of an screw can be calculated by dividing the number of turns per inch.

15. Game

16. Efficiency
Efficiency = the measure of how much work must be put into the machine than the work you get out.
Input Force x Distance = Output Force x Distance
However, some output force is lost due to friction.
The comparison of work input to work output is called efficiency.
No machine has 100% efficient due to friction.

17. Mechanical Advantage
Input force (the force you apply) and the output force (force which is applied to the task)
MA = output/input
Output force > input force = mechanical advantage greater than one.
Output < Input force = Less than 1 = less mechanical advantage