1. Section 2
Simple Machines

2. I. Types of simple machines
Simple Machine-a machine that does work in one motion.
There are six types of simple machines.

3. B. Levers – bar that is free to turn about a fixed point.
The fixed point is called a fulcrum
Resistance arm
Effort arm
fulcrum
Resistance Force

4. 2. Three classes of levers:

5. What Class?
Third Class
First Class
Second Class

6. C. Pulley – a grooved wheel with a rope, chain, or cable running along the groove.
Fixed pulley-attached to a fixed object.

7. D. Wheel and Axle – two wheels of different sizes that rotate together.
usually the effort force is applied to the larger wheel.

8. E. Inclined Plane – sloping surface that reduces the amount of force required to do work.

9. F. Wedge – inclined plane with one or two sloping sides

10. G. Screw – inclined plane wrapped in a spiral around a cylindrical post.

11. Mechanical Advantages of Simple Machines

12. II. Mechanical advantage (MA)
A ratio of the output force and the input force
MA greater than one = multiplying the input force
2. MA less than one = increase distance or speed.

13. Length of resistance arm
B. Lever
Length of effort arm
MA =
Length of resistance arm Le
MA = Lr

14. C. Inclined Plane
length of slope
MA =
height of slope l
MA = h
Effort distance
MA =
Resistance distance

15. D. Pulley
1. Fixed pulley, MA = 1
E. Wheel & Axle
Radius of wheel
MA =
Radius of axle rw
MA = ra