Here's why:
* Electromagnetism: While protons in the nucleus have positive charges and repel each other, electromagnetism isn't strong enough to overcome this repulsion at such close distances.
* Weak nuclear force: This force is responsible for radioactive decay and is not involved in holding the nucleus together.
* Gravity: Gravity is the weakest of the four fundamental forces and plays a negligible role in the nucleus.
* Strong nuclear force: This force is incredibly powerful but acts only over extremely short distances (within the nucleus). It's responsible for attracting protons and neutrons together, overcoming the electrostatic repulsion between protons and holding the nucleus stable.
In summary, the strong nuclear force is the glue that binds the nucleus together.
