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Torque and inertia

  1. Aug 2, 2010 #1
    After all this recent talk of torque and power I figure I can post my stupid question of the week:

    How does torque relate to inertia?

    Say I have a nice balanced wheel that I want to spin. I can calculate the moment of inertia but I'm too old to remember how to figure out how much torque and/or power I need to over come the inertia (and friction) to get it going. I got stalled here in dimensional analysis:

    moment of inertia == kg·m²
    energy (joules) == kg·m²/s² (Newton-meters)
    torque == joules/radian == kg·m²/s² (same as energy but through X degrees of rotation)
    From wiki: A torque of 1 N·m applied through a full revolution will require an energy of exactly 2(pi) joules.

    So, now ignoring friction, can I figure that the driving torque just influences the acceleration? And then it's only friction that keeps my wheel from spinning when the motor is too small?
  2. jcsd
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