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Homework Help: What does this equation mean? Physics Work.

  1. Oct 19, 2011 #1
    This equation is given on my equation sheet for Work but I'm not sure what the sub s stands for. This isn't really a homework question but I'm asking it in this thread because it may help me with my homework. Can someone explain this equation to me? Thanks!

    Fs = -kx

    Some sort of Force is equal to negative kinetic energy times displacement in the x direction? What force, when do I use this equation?
  2. jcsd
  3. Oct 19, 2011 #2
    Force exerted on spring, possibly.

    It's the equation that you have probably encountered in relation to Hooke's law. Where k is the spring constant and x is the distance stretched/travelled.
  4. Oct 19, 2011 #3


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    Gold Member

    Fs simply means the Force of s - whatever s is. The s is arbitrary and simply denotes what F it is referring to.

    If you had air and water pressing on a bladder, you might use Fa and Fw
  5. Oct 19, 2011 #4


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    Science Advisor

    Yes, this is Hooke's law- the force due to a spring is proportional to the distance it is stretched or compressed. F is the force, and x is the amount of stretch or compression. "k" is not "kinetic energy", it is the constant of proportionality. If F is in Newtons and x is in meters, then k is measured in Newtons per meter.
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