A person scuffing her feet on a wool rug on a dry day accumulates a net charge of $-28 \; \mu \textrm{C}$. How many excess electrons does she get, and by how much does her mass increase?

VIDEO TRANSCRIPT

This is Giancoli Answers with Mr. Dychko. The number of electrons accumulated by a person when scuffing their feet on a wool rug on a dry day is is one electron for every 1.602 times ten to the minus 19 coulombs times the 28 micro Coulombs they accumulated and the prefix micro means multiply by ten to the minus six. And this works out to 1.7 times ten to the 14 electrons and the change in mass of the person will be this many electrons multiplied by the mass per electron of 9.11 times ten to the minus 31 kilograms per electron. And this gives 1.6 times ten to the minus sixteen kilograms of mass accumulated by this person which is immeasurably small.