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Information About

Spherical Pendulum




It consists of a Mass moving without Friction on a Sphere . The only Force s acting on the mass are the Reaction from the sphere and Gravity .

It is convenient to use Spherical Coordinates and describe the position of the mass in terms of (r, heta,\phi), where ''r'' is fixed.

The Lagrangian is

:
L= rac{1}{2}
m\left(
r^2\dot{ heta}^2+r^2\sin^2 heta\ \dot{\phi}^2
ight)
+ mgr\cos heta.


The Euler-Lagrange Equations give

:
rac{d}{dt}
\left(mr^2\dot{ heta}
ight)
-mr^2\sin heta\cos heta\dot{\phi}^2+
mgr\sin heta =0

and
:
rac{d}{dt}
\left(
mr^2\sin heta
\,
\dot{\phi}
ight)
=0

showing that Angular Momentum is conserved.