1. 6.3 – Simple Machines
Guided notes

2. Objectives
Describe and identify examples of the six types of simple machines.
Explain how the different types of simple machines make work easier.

3. Simple Machines A machine that does work with only one movement
Two Families
Levers – levers, pulleys, & wheel and axle
Inclined Planes – inclined plane, screw, & wedge

4. Lever Bar that is free to pivot about a fixed point
Fixed point = fulcrum
Input arm is part on which input force is applied
Output arm is part that exerts the output force

5. Classes of Levers First Class Lever Second Class Lever
Third Class Lever

6. First-class Levers Fulcrum is located between input and output forces
Multiplies and changes direction of force

7. Second-class Levers
Output force is located between input force and fulcrum
Always multiplies force

8. Third-class Levers Input force is between output force and fulcrum
Doesn’t multiply force but does increase distance over which force is applied

9. 3rd class lever Input force- your hand squeezes the stapler
Output force- the staple goes through the papers
Fulcrum

10. Lever & Ideal MA
Calculating ideal mechanical advantage (IMA) of a lever:
IMA = length of input arm divided by length of output arm

11. Pulley
A grooved wheel with a rope, simple chain, or cable running along a groove
Modified first-class lever
The point in the middle
of the wheel is the fulcrum
The rest of a wheel
acts like the rigid arm.

12. Types of Pulleys Fixed = attached to something and doesn’t move
Force is not multiplied but direction is changed
IMA = 1

13. Types of Pulleys
Movable = has one end of the rope fixed and the wheel free to move
Multiples force
IMA = 2

14. Types of Pulleys
Block & Tackle = system of pulleys consisting of fixed and movable pulleys
IMA = number of ropes supporting the weight

15. Block and Tackle
Pulley website

16. Wheel & Axle
Machine with two wheels of different sizes rotating together
Modified lever

17. Wheel & Axle IMA = radius of wheel divided by radius of axle
Gears are modified forms

18. Inclined Plane
Sloping surface that reduces the amount of force required to do work

19. Inclined Plane
IMA = length of slope (input distance) divided by height of slope (output distance)
Less force is required if ramp is longer and less steep

20. Screw
Inclined plane wrapped in a spiral around a cylindrical post

21. Wedge Inclined plane with one or two sloping sides

22. Compound Machine
Uses a combination of two or more simple machines

23. Cool Links
Simple Machines

24. In-Class Assignment/Homework
6.3 Reinforcement WKT