# Equilibrium

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Equilibrium is when all the net external forces that act upon an object are balanced.  This does not mean all the forces are equal to each other.  If the net force is zero, then the net external forces in any direction is zero.  Any object that is at rest is in equilibrium.

 $$\large{ F_{net} = 0 }$$

## Formulas that use Distance from Equilibrium

 $$\large{ x = x_0 - \frac{ F }{ k_s } }$$

### Where:

$$\large{ x }$$ = distance from equilibrium

$$\large{ F }$$ = force

$$\large{ k_s }$$ = spring force constant

$$\large{ x_0 }$$ = spring equilibrium position

## Formulas that use Spring Equilibrium Position

 $$\large{ x_0 = \frac{ F }{ k_s } + x }$$

### Where:

$$\large{ x_0 }$$ = spring equilibrium position

$$\large{ x }$$ = distance from equilibrium

$$\large{ F }$$ = force

$$\large{ k_s }$$ = spring force constant