Final answer:
A plastic rod becomes negatively charged and the fur becomes positively charged after rubbing. They are charged due to transfer of negative charge from the fur to the rod. Opposite charges attract, which explains the interaction between different objects.
Step-by-step explanation:
When you rub a plastic rod with fur, the plastic rod becomes negatively charged and the fur becomes positively charged. This is because tiny amounts of negative charge are transferred from the fur to the plastic rod. As a consequence, the plastic rod has more negative charge than positive charge, resulting in a net negative charge. Conversely, the fur loses some negative charge and thus has a net positive charge after the interaction.
In the world of electrostatics, opposite charges attract and like charges repel. For instance, if you were to take two plastic rods that had been negatively charged by rubbing with fur, they would repel each other because they have the same charge. On the other hand, if you had one negatively charged rod and one positively charged fur, they would attract each other.
Lastly, it is worth noting that when materials like glass and silk interact in a similar manner, the glass rod becomes positively charged while the silk becomes negatively charged. Thus, the dust is attracted to these materials not due to a third type of charge, but because the dust particles become polarized in the presence of charged objects, leading to attraction.