Is there anything more to forces than being mathematical machinery?

[Adesh]

As I see it, the force found its existence due to the philosophy of causation. Its hard to think that motion can be caused without any cause. And we see that due to this philosophy we something called "Fictitious Forces", these fictitious forces do not exist (no one is there to cause them) but the motion is caused so we have to accept their existence.

 

[Dale]

As I see it, the force found its existence due to the philosophy of causation. Its hard to think that motion can be caused without any cause.

I think that is a very tenuous position to hold given Newton’s first law

 

[FactChecker]

As I see it, the force found its existence due to the philosophy of causation. Its hard to think that motion can be caused without any cause. And we see that due to this philosophy we something called "Fictitious Forces", these fictitious forces do not exist (no one is there to cause them) but the motion is caused so we have to accept their existence.

Where you say "motion", you really should be saying "acceleration". In a Newtonian inertial coordinate system, there is no unexplained acceleration. The "fictitious forces" are there to allow us to study acceleration in non-Newtonian coordinate systems. It is just a computational convenience with no philosophical implications.

 

[sophiecentaur]

I think that is a very tenuous position to hold given Newton’s first law

In the context of this discussion, I would say that N1 is no more than a self referential statement. It more or less says that All Things behave like this. No real causality is implied.

 

[DrStupid]

No real causality is implied.

According to N1 force is the cause and the change of motion the effect. How is this not a causality?

 

[etotheipi]

I thought that Newton's first law is just a statement that there exist inertial frames of reference in which objects remain at rest or in constant rectilinear motion if no forces act on them. I think that's along the lines of what @sophiecentaur was saying (correct me if I'm wrong!).

 

[DrStupid]

I thought that Newton's first law is just a statement that there exist inertial frames of reference in which objects remain at rest or in constant rectilinear motion if no forces act on them.

I usually refer to the original wording. That reads in the English translation:

Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.

That means that forces are the only cause for changes in the state of motion of bodies. Frames of references are not even mentioned.

 

[Adesh]

I usually refer to the original wording. That reads in the English translation:
That means that forces are the only cause for changes in the state of motion of bodies. Frames of references are not even mentioned.

I think those are really the original words.

 

[etotheipi]

That means that forces are the only cause for changes in the state of motion of bodies. Frames of references are not even mentioned.

Right, but the notion of an inertial reference frame is implied. If you sit in a car that accelerates, everything outside the window will accelerate backward without any real forces being applied.

I just treat the first law as the definition of an inertial frame of reference.

 

[vanhees71]

Nevertheless this holds only for inertial frames of reference. The 1st Law rather states that there are reference frames, where this 1st Law holds, the inertial frames. Then the 2nd Law says that the causes of changes of the state of motion (the deviation from rectilinear uniform motion) are forces, which are equal to $\dot{\vec{p}}$, where for a point particle $\vec{p}=m \vec{a}$ with $m$ a measure for inertia ("inertial mass") and $\vec{a}$ the acceleration of the particle relative to the inertial reference frame.

 

[jbriggs444]

I usually refer to the original wording.

Not usually the best approach. The ideas have been polished and refined since Newton first stated them.

That means that forces are the only cause for changes in the state of motion of bodies. Frames of references are not even mentioned.

A more modern view is that cause and effect are irrelevant. If there is a change of momentum, there is a net force. If there is a net force, there is a change of momentum. The two concepts are not cause and effect -- they are more nearly synonymous. We adopt the definition that a "force" is a transfer of momentum and that an "inertial frame" is one in which Newton's first law holds good.

 

[Adesh]

Then the 2nd Law says that the causes of changes of the state of motion (the deviation from rectilinear uniform motion) are forces,

That’s what I believe and have found that same expression expressed by some other well known physicists (including you).

 

[etotheipi]

some other well known physicists

You mean Newton? He's pretty well known, I guess.

 

[Adesh]

You mean Newton? He's pretty well known, I guess.

Mr. Feynman, Mr. Arnold Sommerfeld and few others too.

 

[sophiecentaur]

According to N1 force is the cause and the change of motion the effect. How is this not a causality?

Science has ‘identified’ a common but rather slippery intermediate agency - a Force- which takes the place of all other real agencies: horses, falling water, a spring, a magnet etc.. The term Force allows us a common concept that can be treated a bit like money. We can earn money from many sources and spend it in many ways. Maths is what helps us deal with quantities involved. You could say that the causality is between the tennis player and the ball and the force just allows you to appreciate the quantities involved.
Our brains treat both forces and money as if they are real but they’re only in your head. I thing this justifies the OP and you can choose validly to look at things that way.

 

[Dale]

Since the OP has been answered and this thread is now veering off into a repetition of a discussion that was previously closed it is time to close this thread also.