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Homework Help: Basic circular motion problems

  1. Nov 16, 2006 #1
    A protractor is made so that the edge of its scale is 7.5 cm from the center point. If the scale is marked in degrees, how far apart are the marks along the edge?

    I just thought this would be 360/7.5 but it's not. I'm not sure If I got the question correct.

    A 12-inchdiameter phonograph record rotatesaboutits center by one-quarter turn. a) Thorugh how many radians has it turned? b) How far has a point on the rim moved?

    For a, I got pi/2 which I think iscorrect, but for b, I don't know what to do..........
    Last edited: Nov 16, 2006
  2. jcsd
  3. Nov 16, 2006 #2
    can i get some help?
  4. Nov 17, 2006 #3


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    What is the circumference of a circle in terms of its radius?
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