4/8/09
Post date: Apr 07, 2009 5:17:34 PM
Bell Ringer: What is Work?
Work
What does "work" mean in your lives?
In physics, work = Force * distance, measured in Joules (J)
Force must be in same direction as motion for work to be done
Example: Lifting a weight vs. holding a weight.
Example: Stepping up on a chair
If force is NOT in same direction, first find the component of the force in the direction of the objects movement
Example: Lawn mower
Practice: Page 202: 7
Power
What does "power" mean in your lives?
In physics, power = work / time, measured in Joules per second (J/s) or Watts (W)
Example: Page 203: 9
Practice: Find your inner power!
Step up and down on a chair 10 times in a row while a partner times you. Calculate the total work you do and divide by the time it took you to do it to find your power.
Answer the following questions: 1. How many 60 W light bulbs could you power? 2. How many of you would it take to power a 40,000 W care engine?
Work and Power Assignment
1/2 sheet assignment
Page 213: 1, 3, 9, 18, 19