I was driving by my uncle's farm last weekend, and I went down a really steep hill which has a stop sign at the bottom. Since the road was pretty icy, I got a little nervous, but I stopped, and all was well. Clearly, the physics involved is that I was going down an incline with little friction, which made it harder to stop the car. The coefficient of friction for rubber on ice is 0.15, which is very small, even though the road wasn't all ice. My cousin also decided to do donuts in his icy driveway, which involves a lot of physics too, but that's not something you think about when you might be about to die.