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Strings and Spring

  1. Nov 17, 2003 #1
    I have the following problem

    Pulling up on a rope, you lift a 4.25-kg bucket of water from a well with an acceleration of 1.80 m/s². What is the tension in the rope?

    What part exactly does the acceleration play in this scenario?
     
  2. jcsd
  3. Nov 17, 2003 #2

    Doc Al

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    Staff: Mentor

    The net force on an object determines its acceleration. Given the acceleration, you can find the net force. Tell us what you know about Newton's second law.
     
  4. Nov 17, 2003 #3
    net force = ma
    a = f/m
    1.80 = f/4.25
    f = 7.65
     
  5. Nov 17, 2003 #4

    Doc Al

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    First step: Describe all the forces acting on that bucket! Then add them up to find the net force.

    Draw yourself a diagram.
     
  6. Nov 17, 2003 #5
    there is the force of me pull it up @ 1.80m/s²
    the mass 4.25 pulling down...
     
  7. Nov 17, 2003 #6

    Doc Al

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    There is a force pulling up, that's the tension (T) in the rope. There's also a force pulling down, the weight (not mass!) of the bucket&water. (Note: gravity pulls on the mass, that pull is the weight. You can calculate the weight by multiplying the mass by g, the acceleration due to gravity. g = 9.8 [m/s2])

    The net force is (choosing up as positive):

    Fnet = T - mg

    From Newton's second law:

    Fnet = ma

    Now it's your turn. You know a (it's 1.8 m/s2 upwards) and you know m . Find T. Give it a try.
     
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