Pendulum collision and elastic collision

[ihateap]

1. Homework Statement
2 pendulums collide and stick together after being released from rest at angle Ø (each one is at Ø)
pendulum 1 mass is 2m, pendulum 2 mass is m
What is the final swing angle of the stuck together masses? in what direction is the swing?

repeat for elastic collision

2. Homework Equations
Ui+Ki+Win-Wout=Kf+Uf (conservation of energy)
conservation of momentum


3. The Attempt at a Solution
a very sad one

sorry i couldn't put a picture up, even though it would help a great deal
but any suggestions would help
and if you couldn't tell it has to be solved symbollically

 

[Dick]

They will collide at angle phi=0 (the lowest point on the pendulum), right? What is the velocity (and hence momentum) of each pendulum just before they collide? If they stick together, then after the collision you have a single object with the same momentum. What's it's velocity? Translate that into to how high it will go, and what the angle is. Try and start answering some of these questions. It will make for a much improved 'attempt at a solution'.