Inside the body the heart is pumping blood, the digestive system is grinding away on breakfast, receptors are driving molecules across cell membranes. We do work even as we sleep. Forces causing displacement are happening everywhere under our skins. The human body is a busy place.
courtesy of: The Physics Hypertextbook
I don’t know why I like this so much…It just endears the body to me. It makes even physics seem bearable 🙂