Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Energy (spring) Question

  1. Nov 4, 2006 #1
    I have a question involving the spring costant:

    A 2-kg block is attached to a horizontal ideal spring with a spring constant of 200N/m. When the spring has its equilibrium length the block is given a speed of 5 m/s. What is the maximum elongation of the spring?

    To my understanding when the spring is at its equilibrium length, isn't there no force acting on the spring. So how would you work around it to solve for length. I would appreciate help in how to go about solving the problem. Thank you.
  2. jcsd
  3. Nov 4, 2006 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    That is a bit confusing question. I'm guessing it means that the spring is stretched initially, then released, and the block has a speed of 5m/s as it passes the equilibrium point of the spring. Use the conservation of energy principle
    initial KE of block plus initial PE of spring = final KE of block plus final PE of spring. A couple of those terms are 0.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook