- #1
Simfish
Gold Member
- 823
- 2
Homework Statement
1. A double pendulum, consisting of a pair, each of mass m and length
l, is released from rest with the pendulums displaced but in a straight
line. Find the displacements of the pendulums as functions of time.
===
So... this is a problem from Kibble's Classical Mechanics. Anyways, I can easily get the eigenvalues, eigenvectors, and normal modes for the double pendulum. But the problem is - I can't get the coefficients of the system unless I get a full set of initial conditions. Am I missing something? You need 4 sets of ICs to fully solve the approximation to this problem. The problem is -that you only know that the time derivatives (at time 0) are 0. As for the positions at time 0, all we know is that they're displaced in a straight line. But that just specifies one in relation to the other, and they could be fully horizontal. Or they could be displaced by any arbitrary angle...