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Homework Help: Spring constant of the spring

  1. Nov 7, 2004 #1
    A mass of 100g causes a vertical spring to stretch by 2.0 cm (a) Find the spring constant of the spring in N/M. (b) How much force will cause the spring to compress by 0.5 cm?

    Can some help me? How do u do this? What formula do I have to use?
     
  2. jcsd
  3. Nov 7, 2004 #2

    Galileo

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    If the mass is stationary, the net force acting on it is zero.
    Gravity exerts a force on the mass downwards.
    The spring exerts a force on the mass upwards.
    Since the net force is zero, these must be equal.
    The force of the spring is given by Hooke's law.
     
  4. Nov 7, 2004 #3
    Hooke's law is : mg = k(y-yo)

    so that would be: k= (mg)/(y-yo)
    k= ((.100kg)(9.81m/s^2))/(.02m-yo)

    What is yo?
     
  5. Nov 7, 2004 #4

    Galileo

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    Here y0 would be the y-value when the string is not streched or compressed.
    So that y-y0 measures the displacement from equilibrium of the spring.
    In your problem y-y0 is 2.0 cm.
     
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