# Force Exerted by Contracting or Stretching a Material

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Any strain exerted on a material causes an internal elastic stress.  The force applied on a material when contracting or stretching is related to how much the length of the object changes.

### Force Exerted by Contracting or Stretching a Material Formula

$$\large{ F = \frac { \lambda A l_c } { l_o } }$$

Where:

$$\large{ F }$$ = force exerted

$$\large{ l_c }$$ = change in length

$$\large{ l_o }$$ = origional length

$$\large{ \lambda }$$  (Greek symbol lambda) = modulus of elasticity

$$\large{ A }$$ = origional cross-section area through which the force is applied

Tags: Equations for Force