Astronomy Fundamentals

Medieval Andrenaissance Astronomy

What is Newton’s Third Law of Motion?

According to Newton’s Third Law, “To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal and directed to contrary parts.” That means that to exert a force on an object the thing doing the exerting must experience a force of equal strength in exactly the opposite direction. This law explains, for example, why an ice skater goes backward when she pushes another skater forward.


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