(II) When an object such as a plastic comb is charged by rubbing it with a cloth, the net charge is typically a few microcoulombs. If that charge is 3.0 C, by what percentage does the mass of a 9.0-g comb change during charging?

1.9*10^-13 %

Explanation:

One electron represents -1.6*10^-19 C

3 μC are equivalent to 3*10^-6 C

After loss 3 μC, the amount of electron loss is:

e = (-3*10^-6) / (-1.6*10^-19) = 1.875*10^13

One electron has 9.10938356*10^-28 grams, then the mass lost is:

m = 1.875*10^13 * 9.10938356*10^-28 = 1.7*10^-14 g

The percentage loss is:

(1.7*10^-14 / 9) * 100 = 1.9*10^-13 %

potential energy is directly proportional to height.

more height = more potential energy.

greatest increase in height = greatest increase in potential energy

where are the points with the greatest increase in height ?

has to be c-e or d-e .