Question

describe an simple example to show that total charge on a pair of objects that have been rubbed together is zero

Answer 1

when a glass rod rubbed against a silk cloth then glass object acquired positive charge and silk acquired negative charge the amount of charge acquired by both object must be equal so that the net charge of the system is zero this is so because the according to the law of conservation of charges charge can neither be created nor can it be destroyed

Answer 2

I think what the other answer is,was actually correct.