B Where does the figure for a proton's rest mass come from?

[recniabsal]

TL;DR

The proton rest mass value calculation of

The proton rest mass value calculation of 1.672,621,71?, times 10 inverse 27 kg, where does the figure originate from? What kind of figure is it?

 

[DaveC426913]

1.672,621,71x 10^-27 is not a calculation; it is just a (very small) number.

1.672,621,71x 10^-27kg is the mass of a proton.

Do you mean how did we determine how much a proton masses? Did you try Googling that to see where it leads you?

Hint: Read up a little on "Penning Trap".