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Homework Help: Springs and masses

  1. Oct 31, 2006 #1
    A spring with k = 47 N/m hangs vertically next to a ruler. The end of the spring is next to the 15 cm mark on the ruler. If a 2.7 kg mass is now attached to the end of the spring, where will the end of the spring line up with the ruler marks?

    I got the answer to be 141 cm because I thought that the 15cm is to be converted into meters, can anyone help me with this question?
     
  2. jcsd
  3. Oct 31, 2006 #2
    yes the cm should be converted to metres

    what is the extension as a result of the mass being attached?
     
  4. Oct 31, 2006 #3
    I got 141 cm but thats not correct. I cant figure out the correct answer.
     
  5. Oct 31, 2006 #4
    how did u get that?
     
  6. Oct 31, 2006 #5
    I used 0+mg(0.15m + change in y)=0+ .5k(change in y)^2
     
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