1. Work, Power, and Machines
Intro to Physics

2. Work and Power Work Force x distance In direction of motion N m
joules (J)
What is the work done by a
weightlifter lifts a 1500 N barbell
Over his head to a height of 2.0 m?

3. Work and Power Power Your Power? Rate watt (W) Horsepower Ex.
1hp = 746 W
Ex.
P.415 #2
Your Power?

4. Work and Machines Machine Work in always more than work out
Change force
Size, direction, distance acts
Work in always more than work out

5. Mechanical advantage and efficiency
X increases input force
Actual mechanical advantage
Output/input
Ideal Mechanical Advantage
Input distance/output distance
Example
P. 425

6. Simple machines Lever Fulcrum IMA First Class Input arm/output arm
Fulcrum between input and output forces

7. Simple Machines Second Class Third Class
Output between input and fulcrum
Third Class
Input between output and fulcrum

8. Simple Machines Wheel and Axle Inclined Plane
IMA = radius input/radius output
Inclined Plane
IMA = distance traveled/height raised

9. Simple Machines
Wedge
Screw
threads

10. Simple Machines Pulleys Compound Machines
IMA = # rope sections supporting load
Fixed
Moveable
System
Compound Machines