Instructional Video
Bozeman Science

Bozeman Science: Contact Forces

9th - 10th
In the following video Paul Andersen explains how contact forces result from interatomic forces. [5:29]
Instructional Video
Khan Academy

Khan Academy: Springs and Hooke's Law: Intro to Springs and Hooke's Law

9th - 10th
A video lecture that discusses spring force, restoring force, and gives a good introduction to Hooke's Law. [10:05]