1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

PE of weight on a spring

  1. Apr 29, 2012 #1
    1. The problem statement, all variables and given/known data
    A spring of length 75cm has a mass of 0.5kg hanging from it.
    If the spring constant = 40N/m calculate:
    a) the extension of the spring
    b) The change in PE of the mass


    2. Relevant equations
    Part (a) is easy x = (0.5 x 9.81)/40 = 0.123m
    Part (b) energy = 0.5kx^2 gives 0.30J which is WRONG !!!!

    WHY ?????


    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 29, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi Emilyjoint! :smile:
    that's the energy of the spring

    (energy is not conserved … if you released the mass from rest, it would sail through that equilibrium position at high speed, wouldn't it? :wink:)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: PE of weight on a spring
  1. PE, springs, energy (Replies: 2)

Loading...