Electromagnetism
Before we begin, watch this video that explains why it is important to study electromagnetism. There are two types of charges, and like charges repel, while unlike charges attract.
When equal amounts of both charge types are combined in an object, it becomes electrically neutral. The forces from balanced charges of opposite types inside a neutral object cancel out when viewed from the outside. This explains why we do not often notice the effects of electromagnetism directly, which creates the impression that it must be a weak kind of force. In reality, electric forces are much stronger than gravity! We will come back to this in later lectures.
Source: Robert de Mello Koch, https://youtu.be/an8fWwECJVM
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