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Homework Help: Speed of the second hand of a smoothly running analog watch?

  1. Apr 29, 2007 #1
    (a) What is the angular speed of the second hand of a smoothly running analog watch?
    ____ (rad/s)

    i got 0.03 pi
    webassign says "Check the syntax of your response"
    i also tried 0.03, but it's wrong also..

    how do i put my answer?
  2. jcsd
  3. Apr 29, 2007 #2
    In radians. pi=180 radians, so 0.03pi= 0.03*180=5.4 radians.
  4. Apr 29, 2007 #3
    But, w=theta/t=360/60=6 radians/second.
  5. Apr 29, 2007 #4
    hmm, those were all wrong.. i dont know
  6. Apr 29, 2007 #5
    I believe that gives you 6 degrees per second, which still needs to be converted into radians. There are [tex] 2 \pi[/tex] radians in a whole circle.

    From the fact that when you entered "pi" webassign told you to check your syntax, I assume that this problem will not accept pi as part of an answer--if you get an answer with pi, multiply out!
  7. Apr 29, 2007 #6
    360deg/1min = 360deg/60sec = 6deg/sec x 1rad/180deg = 0.03 rad/sec?
  8. Apr 29, 2007 #7
    OH! I get it now..

    360deg/60sec x 2pi rad/360deg = 0.105

    Thanks for the help =]
  9. Apr 29, 2007 #8

    edit: you beat me :). Happy physics!
    BTW, notice that you multiplied and divided by 360o. You could have just started working in radians and saved yourself the trouble (but it would have required thinking in new units to begin with).
    Last edited: Apr 29, 2007
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