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Homework Help: Spring Constant and Period

  1. Jan 26, 2010 #1
    1. The problem statement, all variables and given/known data

    A 200 g mass elongates a spring 3 cm from its equilibrium position. Find the spring constant (k) of the spring in N/m.

    An unknown mass is attached to the same spring and set in motion. If the period of oscillation is 3 seconds, find the value of the unknown mass in kg.

    2. Relevant equations


    3. The attempt at a solution

    I think I've determined part A to be 65.4 N/m. I did this by converting cm->m and g->kg. Then I filled it into the equation...

    k=.2(9.81)/.03 = 65.4 N/m

    Then I plug it into the other equation for part two of the question

    3/2pi (changed to .477 for ease)=sqrt(m/65.4)
    m=14.91 kg

    Mostly what I'm asking for here is a confirmation on my work and if the m at the end of my second equation comes directly in kg or if it needs to be converted first.
  2. jcsd
  3. Jan 26, 2010 #2


    User Avatar
    Homework Helper

    Hi dynamity, welcome to PF.
    Your answer is correct. Final answer is in kg. No need to convert to any thing.
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