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Torque and the angle turned

  1. Jul 16, 2007 #1
    Ok, So if i calculate the torque on an object, how do i then find out the rate at which that object turns?
  2. jcsd
  3. Jul 16, 2007 #2

    Doc Al

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    Given the torque (and the rotational inertia) you can calculate the angular acceleration. The rest is kinematics.
  4. Jul 16, 2007 #3
    Ok, so this is for a snowboarding game..

    What would be an approximate rotational intertia for a snowboader? His mass in the game is 75kg's.

    Or how would I go about working out what his rotational intertia would be? I guess it would depend on the position of your arms and things wouldn't it.

    Could I just approximate the snowboarder to be a solid cylinder or something?
  5. Jul 16, 2007 #4


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    that sounds appropriate to me.
  6. Jul 16, 2007 #5

    Well, there's a list of equations in physics that explain rotational motion:

    [tex]\Sigma\tau = I\alpha[/tex]

    Which allows you to relate torque to rotational acceleration. Then you can do the algebra to solve for, and calculus to integrate, the formula to get, in essence:

    [tex]\Delta\theta = \omega t + 1/2[\Sigma\tau/I] t^2[/tex]

    But also, yes, it is reasonable to assume that the torque will distribute itself in a uniform way on the skier.
  7. Jul 16, 2007 #6


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    The way a snowboarder turns is complicated. A person can twist his body at the waist causing the snowboard to yaw (a similar method is used for unicycles). A person can shift weight on the board front to back and also inwards and outwards with the twist at the waist method to create a lean. A person can also just hop and yaw the snowboard. Leaning on the edges of the snowboard will cause it to turn.
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