Newton’s laws of motion -- Does the 1st Law presuppose the 2nd Law?

AI Thread Summary
The discussion centers on whether Newton's first law of motion is necessary if the second law is already accepted as valid. A scenario is presented involving a mass moving in a circle on a frictionless plane, where cutting the string results in the second law yielding a trivial equation. This example illustrates that without the first law, the second law alone does not adequately describe the mass's subsequent motion. The implication is that the first law provides essential context for understanding motion when forces are not acting. Thus, the first law is foundational for the application of the second law in real-world scenarios.
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Homework Statement
Is Newton‘s first law of motion necessary supposing that we already know that Newton‘s second law of motion is valid?
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feesicksman said:
Homework Statement: Is Newton‘s first law of motion necessary supposing that we already know that Newton‘s second law of motion is valid?
Good question!
 
Consider a mass at the end of a string moving in a circle at constant speed on a horizontal frictionless plane. At some point the string is cut. After the string is cut, the second law says$$0 = 0$$ which is not very useful for describing the motion of the mass.
 
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