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Rotational motion

  1. Nov 9, 2016 #1
    1. The problem statement, all variables and given/known data

    this is a question just to help with my understanding: ....

    when Torque (kg m^2/s^2) and the Moment of Inertia (kg m^2) are known and used to find angular acceleration, .... T(net)/I, are the units for the resulting acceleration rad/s^2

    Thanks :-)

    2. Relevant equations
    ##\tau = I \alpha##

    3. The attempt at a solution
    t = 12 kg m^2/s^2
    I = 3.00 kg m^2

    angular acceleration = torque/I = 12 kg m^2/s^2 / 3.00 kg m^2 = 4 units(?) / s^2
    Last edited by a moderator: Nov 9, 2016
  2. jcsd
  3. Nov 9, 2016 #2


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    Staff: Mentor

    Yes. Angular acceleration is given in radians per second squared ##(rad/s^2)##.

    The radian is sort of a "unitless unit" that appears and disappears as required when working with angular quantities. It's based on a ratio of lengths from the unit circle, where an angle is defined via the arclength along the circle divided by the radius length. It serves to distinguish a quantity as being angular in nature.
  4. Nov 9, 2016 #3
    thank you! :-)
  5. Nov 9, 2016 #4


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    Science Advisor
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    Gold Member

    How about "dimensionless unit"?
  6. Nov 9, 2016 #5


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    Staff: Mentor

    Sure! That's probably better nomenclature. :smile:
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