Electric Force

The way charges attract or repel each other can be described as a force. A charge can exert a push or pull on another charge depending on if the charges are positive or negative. How much force they exert can be figured out using Coulomb’s Law of Electric Force, which is:

where  C = 8.99 x 10⁹ Nm²/C²

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You can’t do an experiment on the planet without gravity playing some part of it (albeit sometimes so small you can ignore gravitational effects) since we’re in the Earth’s gravitational field. The electrical forces will add another force vector to our FBD that can be used when we look at how objects move in reaction to the forces.

Let’s take a look at how this works:

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How much charge do you think is inside a penny? What would happen if you could separate the positive and negative charges? How much force would each bundle of charge experience? Here’s how you find out:

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As a physics student, I wondered how much of a pulling force was between the nucleus of an atom and the electrons. Let’s look at the simplest atom (hydrogen) and find the attractive force between the proton and the electron:

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Wasn’t that incredible how much force was present just between the two? After I figured that out, I wanted to know how much “push” was present between two protons in the nucleus. If you think about it, there’s really no reason for the protons to stick together inside the nucleus because they are all positively charged. Let’s take a look at the iron atom as we figure this out…

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