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!

Lagrangian of the system of two masses

  1. Jun 22, 2012 #1
    I am wondering, how does lagrangian of such system look like?

    24n46zn.jpg

    Will it be:

    [tex]L=\frac{m_{1} \cdot \dot{y}^2}{2} + \frac{m_{2} \cdot \dot{x}^2}{2} +\frac{m_{3} \cdot (\dot{y'}^2+\dot{x'}^2)}{2} + \frac{I \cdot \dot{ \alpha }^2}{2} - mgy - mgy' [/tex]

    where:

    [tex]y'=\frac{l}{2}sin(\alpha) [/tex]
    [tex]x'=\frac{l}{2}cos(\alpha) [/tex] ?
     
  2. jcsd
  3. Jun 23, 2012 #2
    x^2+y^2=l^2,so x,y,ω(angular velocity)can be obtained.by the way that is correct
     
  4. Jun 24, 2012 #3
    I'm going to sit down and do this when I get a chance. But for now, it looks like you are only going to need one generalized coordinate to completely define the system. I would use the y-coord of m1.
     
  5. Jun 25, 2012 #4
    Hmm so guys, this is correct (with this additional equation as, andrien wrote: x^2+y^2=l^2), but there is way to do that better using one generalized coordinate, right? Hmm very often this one generalize is an angle + length... but here maybe it could be done with y,x etc.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Lagrangian of the system of two masses
  1. Lagrangian systems (Replies: 0)

  2. Two-mass spring system (Replies: 2)

  3. Two mass spring system (Replies: 9)

Loading...