11/14/08
Post date: Nov 14, 2008 2:41:45 AM
Bell Activity: Wait to get your test back. You have 20 minutes to check your calculations and finish anything you couldn't yesterday.
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?