# Hooke's Law

## Physical Law

Hooke's Law applies to an ideal spring:

$\mathbf F = -k \mathbf x$

where:

$\mathbf F$ is the force caused by a displacement $\mathbf x$
$k$ is the spring force constant.

The negative sign indicates that the force pulls in the opposite direction to that of the displacement imposed.

The strain is proportional to the stress.