Hanging plastic speres static electricity physics question?

five lightweight plastic speres labeled A thru E are all hanging by strings in a row, all next to each other. each is either positive, negative or neutral. A B C D E





whats the charge of each if:


A attracts ALL the others.


B attracts A,C,D ... but has no effect on E


a positive charge repels C





please explain why .. i know opposites attract and like charges repel .. im not sure how neutrals react to each though. my physics book does not explain this, its not in my notes, so please teach me these simple physics ideas. (its amazing how crappy these $170 textbooks are!) ..

Hanging plastic speres static electricity physics question?
First of all, opposite charges attract, like charges repel AND


charged objects attract neutral objects.





Start with the last statement...since a +ve charge repels C, C must be +ve. Since B and E have no effect on each other, this is only possible if they are both neutral. Since A attracts all of the others, it must be negative (if it were +ve, it would repel C and if it were neutral, it would have no effect on B and E). Finally D must also be +ve since it attracts to both A (negative) and B (neutral).





So, in conclusion:





A - negative


B - neutral


C - positive


D - positive


E - neutral