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!

Spring (with mass) kinetic energy -- velocity assumption

  1. Sep 7, 2015 #1
    why we assume that velocity decreases linearly in a spring (i.e. if one end is fixed, then velocity of a particle (of spring) at x from fixed =vx/l where v is the velocity of the free end) and why does it hold good too when the spring (linear mass density) is non uniform....

    EDIT: spring has mass..
    ref : https://en.wikipedia.org/wiki/Effective_mass_(spring–mass_system)
  2. jcsd
  3. Sep 7, 2015 #2


    User Avatar
    2017 Award

    Staff: Mentor

    If every part of the spring compresses in the same way, that's the result.
    Not all springs are uniform - if they are not, you might need a different relation between distance and speed.
  4. Sep 8, 2015 #3
    by using spring constant inversely proportional to length and letting a element y from fixed end and Fnet=0 on it so,
    where L is the length of spring at any time t, now, y/x1=(L-y)/x2
    x1+x2=x these are lim->0 inst changes and x1 = velocity of element and solving eqn , v=y/l(v of free end)

    and, since we have not touched linear mass density (only used absolute lengths...) it works
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Spring mass kinetic Date
Two spring one mass Feb 16, 2017
I 2 Masses connected by a spring Aug 5, 2016
Spring mass system with applied force kinetic energy May 17, 2009
Kinetic Energy of Springs with Mass Oct 14, 2005