 Let's look at an application of Coulomb's law. We know that two positive charges repel each other, but the strong force holds them together inside a nucleus. Just how strong is the strong force though? Let's find out by looking at a helium nucleus. The two protons inside of a helium nucleus are separated by one femtometer. So we have two protons that attend to the power of negative 15 meters apart. And we want to find the force that they each experience. Now we know that the force they will experience is equal and opposite since they're both positive. So we only need to find the force one proton experiences from the other. The other proton will experience the same amount of force, except in the other direction. The charge a proton has is 1.6 times 10 to the negative 19 coulombs. Coulomb's constant is 8.99 times 10 to the 9 newtons meter squared per coulomb squared. So applying Coulomb's law, we get that the force the proton experiences is 230 newtons. The other proton experiences the same amount of force except in the opposite direction. 230 newtons is the force required to lift a small child. Considering how small the nucleus of an atom is, this force seems way too large. But we have not made a mistake in this case. And the strong force actually opposes this repulsion and holds the nucleus together. This is why there is so much energy released from nuclear fission. We can also find the acceleration that each proton will experience due to the other if there was no strong force holding them together. The mass of a proton is 1.67 times 10 to the power of negative 27 kilograms. Using f equals ma, we can find the acceleration that the proton experiences. Acceleration roughly equals 10 to the power of 29 meters per second squared. Which means if the strong nuclear force wasn't holding the nucleus together, it would take the proton about 10 to the negative 21 seconds to approach the speed of light.