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Homework Help: What Forumla?

  1. Jan 11, 2006 #1
    What formula should I use for this question? I'm thinking hook's law, but It doesnt seem to fit.

    A mass is attached to a spring that has a constant of 100 N/m. The mass vibrates with a frequency of 2 Hz.

    I have to find the value of the mass and how far it streaches. I know I can use hook's law for the streaching part, but I am unsure of how to carry out this problem.
  2. jcsd
  3. Jan 11, 2006 #2
    [tex] T = \frac {1}{f} = 2 \pi \sqrt {\frac {m}{k}} [/tex]
  4. Jan 11, 2006 #3
    Are you sure thats the right one? I mean, it looks as if its finding period not frequency. So wouldnt it be F=1/t= 1/2 pi Sqroot k over m?
  5. Jan 11, 2006 #4
    that's just the general equation. it's up to you to do the algebra that will give you the value that you want.
  6. Jan 11, 2006 #5
    well based on some information I found, the square root of the mass over K is equal to the equasion of L over g. If all things are reletive then, I should be able to switch it as i would when finding frequency.
    Last edited: Jan 11, 2006
  7. Jan 11, 2006 #6
    However, the second question may not have anything to do with hooke's law at all. It may just be F= 1 over 2pi Sqrt g over L

    But I am unsure if g is to be used based on earth's speed of gravity or if I am on the right track at all.
  8. Jan 11, 2006 #7

    why do you do this? the equation i gave you has frequency, mass, and the spring constant. you know two of these, so just solve for the mass.
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