4/4/11

Post date: Apr 03, 2011 5:2:36 PM

• • Bell ringer: What is work? What is power?

  • Hand back and discuss tests

  • 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

  • Power

    • Rate at which work is done or energy is used (will discuss energy later)

    • P = W / t

  • Notes - Work and Power

    • "Find your inner power" activity

      • Step up and down on a chair 10 times in a row while timing yourself.

      • To find work for 1 time up on the chair, use your weight as the force (1 lb = 4.45 Newtons) and the height of the chair as your displacement (measure in meters)

      • Multiply by 10 to find the work for 10 times.

      • Use P = W / t to find your power output

      • How many 60 W light bulbs could you power?

      • How many of you would it take to power an 88,000 Watt Honda Fit engine?

    • Page 199: 2, 3, 7, 9, 10 due 4/5