Formular for coefficient of friction
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I think the answer is fr = Fr/N. Because friction is a resistive force that prevents two objects from sliding freely

against each other. The coefficient of friction (fr) is a number that is the

ratio of the resistive force of friction (Fr) divided by the normal or

perpendicular force (N) pushing the objects together.

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge