A Radi, HafezO Rasmussen, John2020-02-122020-02-122013Print ISBN 978-3-642-23025-7Online ISBN 978-3-642-23026-4https://t.ly/XdgNZMSA Google ScholarMany simple experiments indicate the existence of electric forces and charges. It is possible to impart an electric charge to any solid material by rubbing it with another material. The rubbed solid material is said to be electrified, or electrically charged. For example, a comb becomes electrified when it is used to brush dry hair. This is justified by observing that the comb will attract bits of paper. Many experiments conducted by Benjamin Franklin reveal that there are two types of electric charges: positive and negative. A glass rod that has been rubbed with silk is commonly used as an example for identifying positive and negative charges. Another common example is a hard rubber rod that has been rubbed with fur. Using Franklin’s convention, positive charges are formed on a glass rod that has been rubbed with silk, and negative charges are formed on a rubber rod that has been rubbed with furenElectrostatic ForceGravitational ForcePoint ChargeResultant ForceElectric ForceBook chapter