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Homework Help: Torque bucket question

  1. Jan 1, 2008 #1
    [SOLVED] torque question

    1. The problem statement, all variables and given/known data
    A bucket filled with water has a mass of 23 kg and is attached to a rope wound around a cylinder with a radius of 0.050 m at the top of a well. What torque does the weight of the water and bucket produce on the cylinder?


    2. Relevant equations
    F=ma
    g=9.8 m/s
    Torque= Force*radius

    3. The attempt at a solution
    just checking if this is the way to go...
    F= 225.4 N
    so torque= 11.27?

    i just plugged in the numbers but i'm not entirely sure of whats going on in this scenario.
     
  2. jcsd
  3. Jan 1, 2008 #2
    The force of the bucket and water is acting on the cylinder. I'm imagining that the cylinder is placed horizontally and its ends secured to the well.

    The torque is defined as the vector product of the force and the distance from pivot that forces an object to rotate. Because of normal forces acting on the cylinder where it is secured, the cylinder is at rotational equilibirum and does not topple over.
     
  4. Jan 1, 2008 #3

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    The torque of a force about a point is the product of the perpendicular distance from that point on the line of action of the force and the force. In this case the weight is acting tangentially on the cylinder, via the rope, and the torque of that force about the axis of the cylinder is the weight X radius of cylinder.

    You should write the torque as 11.27 Nm.
     
  5. Jan 1, 2008 #4
    oh i get it now. thanks!!
     
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