Now you understand how scuffing along a carpet in socks builds up electrons on the body, and how this negative electric charge affects other things (like your cat) when you reach a finger out to touch them. You also know how opposite charges attract and like charges repel, and the difference between balanced charges and unbalanced charges.
We’re going to dive into studying force fields. You may wonder what force fields have to do with a serious examination of physics like the one in this lesson. You probably consider force fields to be something you might hear about in a science fiction scene such as…
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Meanwhile, in section 27B of the Horse Crab Galaxy, First Mate Fred frets, “Captain Clyde! the force field is too strong. Our ship will never make it through.” “Never worry First Mate Fred!” exclaims Captain Clyde calmly. “I’ve increased power to the neutron-frapters so we will be just fine.” “Captain Clyde, that’s genius. You’re my hero!” First Mate Fred fawns.
Truthfully, however, force fields aren’t just something for science fiction writers. They are actually a very real and very mysterious part of the world in which you live. So, what is a force field? Well, I can’t tell you. To be honest, nobody can.
There’s quite a bit that is still unknown about how they work. A force field is a strange area that surrounds an object. That field can push or pull other objects that wander into its area. Force fields can be extremely tiny or larger than our solar system. There are gravitational fields, magnetic fields, electric fields, and electromagnetic fields.
Click here to go to next lesson on Maxwell’s Third Equation.
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Energy is “N/C”, and force is measured in “N”. The problem in the video shows how to find energy by dividing the force in N by the charge in C. The FBD in the problem shows force “F” opposed by the gravitational force “mg”. Does that help?
We were wondering … Why isn’t the force that opposes gravity in this problem (i.e., the electric force) expressed in Newtons? Since mg is in Newtons, having it opposed by a force with units of N/C (Newtons per Coulomb) seemed odd.