No matter what that Intro to Physics book says, you can't calculate the "work done by friction." Nope. Doesn't work. Don't even try it.

Physics and Python stuff. Most of the videos here are either adapted from class lectures or solving physics problems. I really like to use numerical calculations without all the fancy programming ...

“Our work will lead to a deeper understanding of hardness,” Simunek told PhysicsWeb. “The approach will also tell materials scientists how to arrange atoms to make a hard structure for the first time.