Is Newton's Second Law Valid in an Accelerating Reference Frame?

In summary, in a lab frame of reference, Newton's second law is valid in the form of Fnet=ma. However, when considering a reference frame moving past the laboratory frame with a constant acceleration a1, it is not valid. This is shown by comparing the Galilean transformation for a frame moving at a constant speed b and a frame with a constant acceleration a1, where it is found that acceleration is not invariant in the latter case.
  • #1
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Homework Statement


In a lab frame of reference, an observer finds Newtons second law is valid in the form of Fnet=ma. Show that Newtons second law is not valid in a reference frame moving past the laboratory frame of problem 1 with a constant acceleration a1. assume that mass is an invariant quantity and is constant in time.


Homework Equations


f=ma


The Attempt at a Solution


i don't get how to show this, i get how to show that the velocities and displacement would be different but not how to relate that to the force
 
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  • #2
Suppose instead that we wish to show that NSL is valid in a 2nd frame moving at constant speed b. The Galilean (sp?) transformation is

x' = x - bt

where the primed quantities are in the moving frame, and b is some constant speed. If we differentiate this twice with repsect to time, we obtain

a' = a

Since mass is invariant, F = ma holds in both frames.

Now do the same thing, but assume that b = a1 t, also the speed of the moving frame but written in terms of a constant acceleration a1 and time. You should find that acceleration is this case is not invariant.
 

FAQ: Is Newton's Second Law Valid in an Accelerating Reference Frame?

What is the Principle of Newtonian Relativity?

The Principle of Newtonian Relativity, also known as Galilean Relativity, states that the laws of physics are the same for all observers in uniform motion. This means that the laws of motion and mechanics remain unchanged regardless of an observer's relative position or velocity.

How does the Principle of Newtonian Relativity differ from Einstein's Theory of Relativity?

The Principle of Newtonian Relativity is limited to observers in uniform motion, while Einstein's Theory of Relativity includes both uniform and accelerated motion. Additionally, Einstein's theory introduced the concept of the speed of light being the ultimate speed limit in the universe.

Can the Principle of Newtonian Relativity be applied to all physical phenomena?

No, the Principle of Newtonian Relativity is limited to the laws of motion and mechanics. It cannot be applied to phenomena such as light, electricity, and magnetism, which require the use of Einstein's Theory of Relativity.

How did Newton contribute to the development of the Principle of Newtonian Relativity?

Isaac Newton's laws of motion, specifically the first and second laws, formed the basis of the Principle of Newtonian Relativity. He also introduced the concept of absolute time and space, which was later challenged by Einstein's theory.

Is the Principle of Newtonian Relativity still relevant in modern physics?

Yes, the Principle of Newtonian Relativity is still relevant in many areas of physics, particularly in classical mechanics. It is often used as an approximation for situations with low speeds and weak gravitational fields. However, it has been superseded by Einstein's Theory of Relativity in many modern applications.

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