The Manga Guide to Physics

202 Chapter 4 Energy

Springs and the Conservation of Energy

Let’s think about resilience of a spring as an example of the conservation of energy.

When you compress

*

a spring with spring constant k (you can think of k as a measure

of how springy your spring is in N/m) by x (the distance beyond its natural length), the

potential energy stored in the spring can be expressed as follows:

PE = ½ kx

2

This stored energy is called elastic potential energy. If we place a mass m next to

this spring and the opposite side is fixed, what is the force it will receive? And what will its

velocity be?

* Note that springs work the same way if you stretch them, as ...