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Homework Help: Vectors. Adding, subtracting, and velocity questions

  1. Jan 25, 2010 #1
    So I have a few problems that I need help with. Any help would be greatly appreciated as I am new here and stumped.

    1. A woman walks 220 m in the direction 27 degrees east of north, then 205 m directly east.
    (a) find the magnitude (finished it).
    362.5 m

    (b) Find the angle of her final displacement from the starting point.

    (c) Find the distance she walks (finished it).

    2. Suppose a-b=2c, a+b=9c, and c=5i+3j. (***NOTE: all "a","b", and "c" have directional arrows above them I just didn't know how to put them there. The i and j have ^ above them as well).

    (a). What is a?

    (b). What is b?

    5. At one instant a bicyclist is 35 m due east of a park's flagpole, going due south with a speed of 11 m/s. Then, 12 s later, the cyclist is 50 m due north of the flagpole, going due east with a speed of 12 m/s. For the cyclist in this 12 s interval, find each of the following.

    (a) displacement (solved)
    magnitude = 61 m
    direction = 55 degrees north of west

    (b) average velocity (solved)
    magnitude =5.08 m/s
    direction = 55 degrees north of west

    (c) average acceleration
    magnitude = ??? m/s^2
    direction = ??? degrees north of east

    6. A ball rolls horizontally off the edge of a tabletop that is 2.00 m high. It strikes the floor at a point 1.57 m horizontally away from the table edge. (Neglect air resistance.)

    (a) How long was the ball in the air?
    ??? s

    (b) What was its speed at the instant it left the table.

    I am sorry there are so many, I got the majority of them but was very confused on these. At first I thought I new how to do 6 but then I realized that I didn't have the instant velocity in the x direction. All help is greatly appreciated. Thanks again.
  2. jcsd
  3. Jan 26, 2010 #2
    I have answered all except question 5 part c. I got the acceleration, and the angle, but I cannot figure out the magnitude of the average acceleration. Any help?
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