So far in this chapter, we have discussed physical forces that actually exist in nature. But there is no reason why we cannot invent our own. Because our main purpose is to play around with forces and their effects, we don't have to be limited by reality. In the next few sections, we'll introduce different force laws and see what they can do. Feel free to create your own!
A central force is one that satisfies the following two conditions:
- The magnitude of the force depends only on the distance from a given point.
- The direction of the force is always toward that point.
Newtonian gravity, electrostatic forces, and spring forces are all examples of central forces. Mathematically, the above two conditions can be ...