Minimum potential energy of a simple harmonic oscillator

[Abhishekdas]

Homework Statement

A simple harmonic oscillator of force constant 2*10⁶ N/m and amplitude .01 m has total maechanical energy 160 J...

Homework Equations

The Attempt at a Solution

Now this is not the question but what is the minimum potential energy...1/2kx^2 comes out to be 100...suggesting that miniimum PE should be 60...Why is it not zero...i know that for certain shm's mim PE isn't 0 but i thought that for a simple harmonic oscillator its always 0...By the way is a weight hanging down a spring suspended from a ceiling a kind of a simple harmonic oscillator? If so then we can chose reference point in away that PE is non zero...I want some clarification so guys i am waiting for your comments...

 

[jbsteele]

The minimum potential energy of a simple harmonic oscillator is equal to zero. This is the case because the displacement of the object from equilibrium is the only factor that affects potential energy. When the object is at equilibrium, the displacement is zero (x=0). Therefore, the potential energy is 1/2kx^2, which equals 0. A weight hanging down a spring suspended from a ceiling is a type of a simple harmonic oscillator. However, the reference point for potential energy may be chosen such that the potential energy is not zero. For example, if the reference point is chosen to be the maximum displacement of the object, then the potential energy will not be zero.