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Homework Help: Calculating Angular and Linear Speed and period of revolution

  1. Feb 3, 2013 #1
    1. The problem statement, all variables and given/known data
    A toy truck moves around the outside of a circle of radius 0.6m at 2 revolutions per second

    a: the angular speed of the truck
    b: the linear speed of the truck
    c: the period of revolution

    2. Relevant equations
    ω= \frac{2π}{T} \\

    3. The attempt at a solution
    For part a i have done..
    ω= \frac{2π}{T} \\
    ω= \frac{2π}{0.5} \\
    ω= 12.56 rads/s

    I used 0.5 as it says it rotates twice per second so one rotation would take half a second (i think this maybe wrong).

    For part b i have done..
    v=rω \\
    v=0.6 \times 12.56 \\
    v= 7.54m/s \\
    Obviously this depends on whether I got part a correct.

    For part c I am not sure what the question is asking for but at a guess I did what I did in part A..

    2 revolutions per second, therefore 1 revolution would take 0.5s.

    Any help is appreciated.
    Last edited: Feb 3, 2013
  2. jcsd
  3. Feb 3, 2013 #2
    What is 2 divided by .5? Last time I checked it was 4.
  4. Feb 3, 2013 #3
    I understand that, but where does that relate to my answers? Have I divided 2 by 0.5 anywhere?

    I do usually miss obvious things, and I cant see this one, could you point it out please?

    EDIT: sorry I just released this mistake (i think) and rectified it.
  5. Feb 3, 2013 #4
    Last time I looked your first answer was 3.14 rad/sec for angular velocity. Now it has been changed to 12.56 radians/sec.
  6. Feb 3, 2013 #5
    I am not a native English speaker but I think it means the time one rotation takes. So for c T=0.5s
  7. Feb 4, 2013 #6
    Could anyone have another look please and see if there is anything wrong with it now? Any help is appreciated :)
  8. Feb 4, 2013 #7
    It is correct. Angular speed is 4*pi; linear speed is 2.4*pi; period is 0.5 seconds.
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