# Newtons First Law Newtons First Law (described the **Coasting Law** in [Waves in an Impossible Sea](Waves%20in%20an%20Impossible%20Sea.md)). Tightly intertwined with the [Principle of Relativity](Principle%20of%20Relativity.md) it states the following: > An object, if moving steadily and left on its own (unaffected by any push or pull of other objects), will coast forever. It will continue to move steadily at the same speed and in the same direction. While counterintuitive, all we need to do is image the world if there were no friction or air resistance. ### Newton's First Law vs Aristotle's Resting Law Newton's First Law is in direct conflict with Aristotle's [Resting Law](Resting%20Law.md). The Resting Law can be shown to be false via observation, but it suffers from an even deeper conceptual problem: it conflicts with the [Principle of Relativity](Principle%20of%20Relativity.md). Newton's First Law and the Resting Law both agree that stationary objects will remain stationary. But, in terms of moving objects they say: * Newton's First Law: they will keep moving at the same speed and direction. * Resting Law: they will decelerate and stop. So now consider that you had a large rock. In situation A you want the rock to remain stationary. The Resting Law says "no problem that requires no energy". In situation B, you have accelerated the rock to 100 m/s and want to just let it coast forever in the same direction. The Resting Law now says "Hmm, that is going to require an engine and infinite fuel - sorry!". But notice what just happened - the Resting Law assumes a difference between being at rest and steady state motion. That is in direct conflict with the [Principle of Relativity](Principle%20of%20Relativity.md), which specifically states that steady motion is undetectable! By contract, Newton's First Law has no issue coexisting with the [Principle of Relativity](Principle%20of%20Relativity.md). --- Date: 20240705 Links to: [Waves in an Impossible Sea](Waves%20in%20an%20Impossible%20Sea.md), pg 34 Tags: References: * []()