1. Simple Machines

2. Criteria for Success
I will be able to name the six (6) types of simple machines.
I will be able to calculate mechanical advantage given the work input and work output.
I will be able to calculate work given force and distance.

3. Simple Machines
Machines are objects that make it easier for people to do work.
Simple machines have only one or two main parts.
Examples: shovel, screwdriver, knife, broom, slide

4. Using a screwdriver to get the lid off a paint can…
You do work on the screwdriver.
The screwdriver does work on the lid.

5. Mechanical Advantage:
Work input=the work you do on a machine
Work output=the work done by a machine
Machines allow for the same amount of work but less force.

6. Simple Machines Study Guide

7. 1. Levers: A bar that pivots or turns on a fixed point.
A fulcrum is the fixed point.
Examples: seesaw, wheel barrel, fishing pole
1st Class—seesaw
2nd Class—wheel barrel
3rd Class—hammer

8. 2. Pulley Consists of a wheel over which a rope, chain, or wire passes
Example: opening the blinds

9. 3. Wheel and Axle Consists of two circular objects of different sizes
Example: Faucet, doorknob, steering wheel

10. 4. Inclined Plane
A straight, slanted surface
Example: Ramp

11. 5. Wedge A pair of inclined planes that move
Example: knife, doorstops, axes

12. 6. Screw
An inclined plane that is wrapped in a spiral around a cylinder
Example:

13. Compound Machine Made up of more than one simple machine
Example: can opener

14. Label the simple machines in the following compound machine.
Lever
Wheel and Axle
SCREW
Pulley

15. What is work?
Work is done when a force causes an object to move in the direction of the force. Example: Bowling is work. You are exerting force on the bowling ball. The bowling ball is traveling a distance in the same direction as the force of your arm.

16. During work, there’s a transfer of energy.
Force vs. Work…
applying force doesn’t always result in work

17. For work to be done, the object must move in the same direction as the force.

18. Can you calculate work? YES
Work = Force x Distance W = F · d Work (energy) = Joules Force = Newtons Distance = Meters

19. Let’s practice… Work = Force x distance Work = 1,000 N x 150 meters
How much work is done by a crane that lowers 1,000 N of material a distance of 150 meters?
Work = Force x distance
Work = 1,000 N x 150 meters
Work = 150,000 Joules

20. Let’s practice… Work = Force x distance Work = 5.8 N x 2 m
A boulder weighing 5.8 Newtons is lifted 2 meters. How much work is done?
Work = Force x distance
Work = 5.8 N x 2 m
Work = 11.6 Joules

21. Your Turn!
1. If a car is moved 10 meters and 3 Newtons of force is needed to move the car, what amount of work has been done? 2. If a ball is lifted 2 meters off the ground and 5 Newtons of force were needed to move it, what amount of work has been done? 3. The force required to move a chair 4 meters is 3 Newtons, what amount of work is done?