When you took introductory physics, you discovered in regards to the “basic forces.” It goes one thing like this: All interactions are the results of a number of of 5 fundamental forces: sturdy nuclear, weak nuclear, gravity, electrical, and magnetic. “Doing physics,” then, means figuring out the forces in play.
There’s an issue, although, which could not have been talked about: The forces you observe rely in your vantage level—your “body of reference.” Look out the window. Timber, homes, lawns—they’re all stationary, proper? However take a look at that very same spot from house and it’s transferring a thousand miles an hour. It regarded nonetheless to you earlier than since you have been transferring with it.
We’ve this similar drawback with electrical and magnetic fields. Relying in your reference body, what seems to be a magnetic pressure from one spot seems to be an electrical pressure from one other.
Is your mind melting but? Simply wait—it will get even weirder. To grasp what’s happening right here, let’s first take a look at electrical and magnetic forces in isolation.
The Electrical Drive
See all that stuff round you? All the things. It is all made from simply three issues: protons, electrons, and neutrons. That is type of wild when you concentrate on it. Two of those basic particles have an electrical cost: the negatively charged electron and the constructive proton.
If an object has extra electrons than protons, it should have a internet unfavorable cost. So, that sock within the dryer that adheres to all the pieces? It picked up further electrons by rubbing towards different garments. If an object loses electrons it has a constructive cost.
We are able to calculate the electrostatic pressure between two charged objects with Coulomb’s legislation. This says that the pressure between them is determined by the product of their expenses and the way far aside they’re. As an instance, I constructed this high-tech contraption under, which has two little foam blocks hanging on strings. I gave them each a unfavorable cost, which implies they’ll repel one another. Test it out:
