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.
About this quote
- What does it mean?
- Every action has an equal and opposite reaction; forces between two bodies are equal and opposite.
- In plain terms
- When one object pushes another, the second pushes back with the same force.
- What can you take from it?
- Expect reciprocal forces in interactions.
Where it applies
Putting it to work
Questions to consider
- What happens when forces are not aligned?
- How does this principle apply in non‑linear systems?
Another view
It does not address forces that are not directly opposite, such as torque.
More from Isaac Newton
The alternation of motion is ever proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.
Permalink to quote #23 Hypotheses non fingo.
Permalink to quote #25 Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it.
Permalink to quote #22
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