Key Idea.
Section 1
Newton’s Third Law: The Science of Force Pairs
Forces never happen alone; they arise from interactions and always occur as a force pair.
Newton’s Third Law of Motion describes the nature of this pair: for every action, there is an equal and opposite reaction.
Section 2
The Balance of Forces
The most counter-intuitive aspect of Newton's Third Law is the equality of strength. The forces in a collision pair are always identical in magnitude.
This rule applies regardless of size or speed. In a collision between a massive asteroid and a small satellite, the force exerted by the satellite on the asteroid is identical to the force exerted by the asteroid on the satellite. The forces are perfectly balanced, even if the outcomes are not.
Expand to review the lesson summary and core properties.
Section 1
Newton’s Third Law: The Science of Force Pairs
Forces never happen alone; they arise from interactions and always occur as a force pair.
Newton’s Third Law of Motion describes the nature of this pair: for every action, there is an equal and opposite reaction.
Section 2
The Balance of Forces
The most counter-intuitive aspect of Newton's Third Law is the equality of strength. The forces in a collision pair are always identical in magnitude.
This rule applies regardless of size or speed. In a collision between a massive asteroid and a small satellite, the force exerted by the satellite on the asteroid is identical to the force exerted by the asteroid on the satellite. The forces are perfectly balanced, even if the outcomes are not.