What does strong force mean?

Question

Levi Anderson · Accepted Answer

It is one of the four fundamental forces with a very short range.

#color (green)(▪"Electromagnetic force")#
#color (green)(▪"Strong force")#
#color (green)(▪"Weak force")#

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#color (blue)(▪"short range of strong force"(10^-15m)#

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A simple experiment can demonstrate short range of strong force

Consider uranium atom (a heavy element), as the observations suggest it is unstable because of greater repulsive force, if strong force was stronger than electromagnetic force and with a good range as well then the atoms would have been even heavier and lot more stable but it isn't so.
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Consider 2 Protons separated by #1m# , they'll move apart from each other though force and velocity would be too less but yet observable. If strong force had a good range then those protons would have attracted further.

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Strong force also exists between quarks.
A proton & neutron are made up of smaller units called quarks

In a proton, there are 3 quarks (2 up and 1 down).
up quarks have a charge of #+2/3# and down with #-1/3#.
these quarks do repel each other as well but here gluon keeps bouncing between the quarks and hold them together. gluon actually glues sub-atomic particles. gluon is a massless particle so its speed is "c".

Watch these video about strong force

Leah Abbate · Answer

undefined The strong force, also known as the strong nuclear force, is one of the four fundamental forces of nature. It is responsible for holding together the nucleus of an atom by overcoming the repulsive forces between positively charged protons. The strong force is the strongest of the four fundamental forces but operates only at very short distances within the nucleus.