10/5/10

Post date: Oct 05, 2010 2:2:10 PM

• • Bell ringer: a plane has an air velocity (Va) of 255 mph at 29 degrees South of Est and a ground speed (Vg) of 270 mph at 32 degrees South of West. What is the wind velocity (Vw)? (Va + Vw = Vg)

  • Objects on an incline

    • For objects on an incline, we shift our perspective and use a different coordinate system.

    • Instead of X and Y (horizontal and vertical) we use Parallel and Perpendicular (relative to the slope the object is on)

    • Friction is all in the parallel direction, normal force is all in the perpendicular direction, so weight is the only force for which you must calculate the components in the parallel and perpendicular directions

    • w (parallel) = w * sin (angle)

    • w (perpendicular) w * cos (angle)

  • Do page 126: 23-25 for practice