3/7/11

Post date: Mar 07, 2011 2:33:12 PM

• • Bell Ringer: A 20.0 kg object acceleerates at 16.5 m/s/s at 83.5 degrees North of West when 3 forces act on it. If F1 = 455 N at 81.0 degrees North of East, and F2 = 125 N West, what is F3?

  • Objects on an incline

    • Problems are very similar to what we've been doing

    • To make less work for ourselves, we don't work in the X (horizontal) and Y (vertical) directions any more. Instead we work with the parallel (to the ramp) and perpendicular (to the ramp) directions.

    • Friction acts only in the parallel direction

    • Normal force acts only in the perpendicular direction

    • Weight is the only force that has both a parallel and a perpendicular component. To find those components, use the following equations:

• • • Stickiest shoe contest

• • P.126: 23-26 due tomorrow

  • Quiz 6 tomorrow - equilibrium and objects on an incline

  • Bell ringers due tomorrow