# Double Pendulum !

1. Dec 6, 2009

### captainjack2000

Double Pendulum URGENT!

1. The problem statement, all variables and given/known data
I am trying to solve this past paper question for my exam tomorrow:
A double pendulum is constructed using a light rod and light inextensible strings.
Two string pendulums hanging from ceiling 1m long. 0.1m from top they are connected by a light rod.
One mass is knocked to the right. Find the beat period in the subsequent motion.

2. Relevant equations
I know that they will both undergo shm
a=-w^2x but I have no idea where to go from here!!!!

2. Dec 6, 2009

### MaxL

Re: Double Pendulum URGENT!

I don't think I'm allowed to help you with a take-home exam. You better hope your professor doesn't hang out of PF.

EDIT: One day, I'm going to start reading the first post carefully before replying. Today is not that day!

I can't visualise the problem. Is it like this?

................|.......................
................|.......................
......______|_______............
......|...................|.............
......|...................|.............
......O..................O.............

with the rod on top and the pendulums on the side? So the rod is hanging from the ceiling?

Last edited: Dec 6, 2009