quot;In the beginning of the 20th century, some scientists thought that a nucleus may comain both electrons and protons.

Need help with one problem regarding Quantum Mechanics!! 

"In the beginning of the 20th century, some scientists thought that a nucleus may comain both electrons and protons. Use the Heisenberg uncertainty principle to show that an electron cannot be confined within a nucleus. Repeat the calculation for a proton. Comment on your results."

I got the math part. For electrons, delta v = 5.79e10, which is larger than the speed of light. For proton, delta v = 3.15e7, which is smaller than the speed of light, but I don't know how to explain this answer as how it proves that an electron cannot be confined within a nucleus?

Any help is appreciated, thank you in advance!!