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!

Work done by a spring & its potential energy

  1. Nov 14, 2012 #1
    According to work - mechanical energy theorem ,
    W = K(final) - K(initial) + U(final) - U(initial) . . . . (1)
    as we define Potential energy as negative of work done by conservative force and assuming that the only force in this situation is Spring force then ,
    W(spring) = K(final) - K(initial)
    As work done is calculated by finding component of spring force in direction of displacement. How can we say that U(final) - U(initial) applies for all possible conditions of extension of spring as displacement may not be in direction of force ?
    Spring force = 0.5kx2
     
  2. jcsd
  3. Nov 14, 2012 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    First of all, your equation (1) defines the external work done by/on a system. If no energy is added or lost (Wext = 0), Kf + Uf = Ki + Ui.

    Second, your question is not clear. What do you mean when you say U(final) - U(initial) applies? U(final) - U(initial) is not a mathematical statement.

    Finally, your statement: Spring force = 0.5kx2 is not correct. F = -kx.

    AM
     
  4. Nov 14, 2012 #3
    In case this was a simple slip, the formula


    [tex]W = \frac{1}{2}k{e^2}[/tex]

    W = work, e = extension, k = spring constant

    Refers to the work done in extending a spring = potential energy stored in that spring on extension.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Work done by a spring & its potential energy
  1. Work done by a spring. (Replies: 6)

Loading...