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Help calculating forces

  1. Aug 6, 2016 #1

    Please have a look at the diagram. The black circle represents a motor, the green circle represents the rotating shaft of the motor, and the red beam is attached to the motor's shaft. The motor spins the red beam counter clockwise in the direction of the arrows.

    What I need to know is how to calculate the rotational force at point A, and at point B. Thanks.
    Last edited: Aug 6, 2016
  2. jcsd
  3. Aug 6, 2016 #2


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    If the motor produces a torque T then the force at any point along the arm is given by F = T/R where R is the radius (eg the distance from the centre of the motor shaft to the point).

    So if the motor Torque was 10Nm and Point A was 0.1m from the centre then the force at A would be 10/0.1 = 100N. If point B is at 0.2m then the force at B would be 10/0.5 = 50N.
  4. Aug 6, 2016 #3
    Thanks a lot for your help.
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