If you took Introductory physics you learned about “basic forces”. This is something like this: all interactions are the result of one or more of five basic forces: mighty nuclear, frail nuclear, gravitational, electric and magnetic. “Doing physics” therefore means identifying forces in the game.
However, there is a problem that might not mention: the forces you are observing depend on your point of view – your “reference frame”. Look out the window. Trees, houses, lawns – they are all stationary, right? But look at the same place from space and moves a thousand miles per hour. It looked even earlier because you moved with him.
We have the same problem with electric and magnetic fields. Depending on the reference frame, what seems to be a magnetic force from one place seems to be an electrical force from the other.
Is your brain melting? Wait – it gets even strange. To understand what is happening here, let’s first look at electrical and magnetic forces in insulation.
Electrical force
Do you see all these things around you? All. Everything is made only of three things: protons, electrons and neutrons. It’s a bit wild when you think about it. Two of these basic particles have an electric charge: negatively charged electron and positive proton.
If the object has more electrons than protons, it will have a net negative charge. So this sock in the dryer that adheres to everything? He conquered additional electrons, rubbing against other clothes. If the object loses the electrons, it has a positive charge.
We can calculate the electrostatic force between two charged objects by Coulomb law. This says that the strength between them depends on the product of their loads and how far they are from each other. To illustrate this, I built this technologically advanced device below, which has two miniature foam blocks hanging on the strings. I gave them both negative load, which means that they repel each other. Check this: