Question

a person scuffing her feet on a wool rug on a dry day accumulates a net charge of 42mC. How many excess electrons does she get, and how much does her mass increase

Answer 1

The number of gained electrons would be:\[\frac{42nC}{1.60217733 × 10^{-19}C/e}=?\]Once you have that you can calculate the increase in mass by just multiplying that number of electrons times the mass of 1 electron.