# What is a Hooke's spring?

## Answer #1

Level 2 (without higher mathematics)

Answered by Alexander Fufaev

A **Hooke's spring** is an elastic mechanical spring that builds up a *restoring force* \( F \) when stretched or compressed. For a Hooke's spring, the restoring force depends on the deflection \( y \) and increases linearly with the deflection:

**Force (magnitude) - Hooke's law**

Formula anchor $$ \begin{align} F ~=~ -D \, y \end{align} $$

Here, \( D \) is a **spring constant** that indicates how stretchable a spring is.