Inside the nucleus (S)
The nucleus of a titanium atom contains 22 protons and is about 8×10-15m (8 femtometres) in diameter. Calculate the electrostatic force and the gravitational force between two protons on either side of the nucleus.
So why don’t nuclei fly apart......?
Solution
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Solution
The charge on each proton is +e, whilst the mass of each is 1 amu (=1.66×10-27kg)
The electrostatic force:

The gravitational force:

So the attractive gravitational force cannot counter the repulsive electrostatic force between the protons. Instead the protons are bound together by something (aptly) called the strong force. More of that next Semester in Physics 1B.