- #1
fluidistic
Gold Member
- 3,926
- 262
Homework Statement
If I consider a 3 dimensional problem related to a spring pendulum (a mass attached to the end of a spring of constant k and the other end of the spring remains fixed) and I want to find the equations of motion of the mass (for several initial conditions), what system of coordinates would you choose? I'm trying to find the Lagrangian of the system and I chose spherical coordinates to express the position of the mass, its velocity and its kinetic energy. However the expression is really long (5 lines in my draft, I may post what I obtained here if you ask for it), I just wonder if I should have used another coordinate system.
I didn't get any term which canceled out with others. I'm going to redo the arithmetics tomorrow (it's 2 a.m. now) but I don't think I made some error. So is it normal to get an enormous expression for the Lagrangian of the system? Say a roughly 5 times longer Lagrangian than for the common double pendulum system?