I'm taking my first Physics course (it's a foreign language), and in English class we were given a piece of paper on Skating taken from an English Physics textbook. We are having problems with some expressions, such as Inertia. What the heck is inertia? Is it a law? Or an expression? (I checked in my dictionary, found nothing useful) Taken from textbook: Then on the following page, they bring up Newton's First law. Some of my mates said that Inertia and Newton's First law is the same thing. Are they right? How the can it be the same thing? Newton's Law is a law, while inertia is ... well, something else.