# Potential Energy

#### Parallel

1. Homework Statement

A figure is attached.
A string with length L connects two beads with masses M1,M2.
what is the equilibrium point?(in terms of the angle theta,as in the figure)

3. The Attempt at a Solution

well I know that I need to find the potential energy as a function of theta,and then find the minimum.

but I dont know how to express the potential energy in terms of theta

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#### AlephZero

Homework Helper
You know the distance between m1 and m2 is L. To get started, find the distances of m1 and m2 from the rightangle in terms of L and theta.

#### Parallel

well this is easy

for m1 : l*cos(theta)
for m2 : l*sin(theta)

I can't see how this is helping me
(by the way,this is not homework,I'm doing extra problems from the book)

#### AlephZero

Homework Helper
The potential energy of a mass = mgh where h is the vertical distance from some point.

From those lengths, finding the vertical distance of the masses below the right angle (using alpha) is also easy.

#### Parallel

can't believe I didnt see it..really easy

thanks :)