Question

deduce newton first law from the second law.

Answer 1

Newton's first law of motion is important so that you can understand the next two. It states that if an object is not moving, than the net force acting upon it is 0; which is the same amount of force on an object moving at a constant velocity. Many people think that just because an object is moving, a force is constantly acting upon it. This is not the case! The second law states that f=ma. If f=ma=0, according to the first law, than the object is not accelerating, plain and simple. Interestingly enough, the first law of motion was actually written by Rene Descartes, when Newton was still a baby! Now, Descartes's laws of motion were far from perfect. However, his first one was correct, and Newton used this as a basis for his next two laws.
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