When hot air rises from a radiator or heating duct, objects behind it appear to shimmer or waver. What causes this?
All forces are vectors, and all vectors have components describing them. Looking at forces that influence torque makes it clear that they aren't like other forces. Instead of having an x-component and a y-component, we use the radial line to describe them. The two components for a force used in torque are F∥, F parallel, and F⊥, F perpendicular. As you might expect, F∥ is the component that lies directly on the radial line and F⊥ is the one that lies at a 90° angle to it. Only F⊥ has any effect on torque, but you have to think conceptually to understand why. Imagine you're trying to open this door with a hinge by pulling the door handle away from the hinge. You are wasting your time and the best you could do is break the handle. The only good thing to come out of that is that y
