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Homework Help: Question regarding Elastic Potential Energy

  1. Jul 6, 2006 #1
    Hey guys ,
    I got another question , here goes :

    A particle P of mass m is attached to one end of a light elastic string of natural length l whose other end is atached to a point A on a ceiling. When P hangs in equilibrium AP has legth 5/3l. Show that if P is projected vertically downwards from A with speed *squareroot*3gl/2 , P will first come to instantaneous rest after moving a distance of 10l/3 .

    What confuses me , is the distance moved . Does it include the natural length or not ? Please show me the proof :biggrin: ... Geeez ... thanks :shy:
  2. jcsd
  3. Jul 6, 2006 #2
    hmmm .... no one ? I just need to know does the distance includes the natural length =) Can anyone tell me please ?
  4. Jul 6, 2006 #3


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    The question says that it is projected vertically from A which is the point where the string is attached. So the distance includes the length at rest of the string.
  5. Jul 6, 2006 #4
    ahhh , got it .... i'm confuse before that lol . thanks = )
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