Movement contraptions that inspired Newton's 2nd law of motion

[roineust]

Besides gravity that always works perpendicular to Earth and thus pulls apples from apple trees towards the ground, there must have been some sort of mid 17th century human made contraption, that used a constant force, produced to move objects with or without wheels, in a direction parallel to Earth (to ground), which Issac Newton was familiar with and which helped him generalize his 2nd law of motion, as a law that is not only true for gravity force, but for any applied force, in any direction.

I was first looking for early inventions of steam engines coupled to wheeled vehicles, but this seems to have been developed at least 100 years later than 23 years old Newton. Perhaps it is some sort of rope that is twisted and acts like a primitive motor, which moves objects in parallel to the ground, like a toy plane or a toy car, propelled by a rubber band? Perhaps it was wind power, applied on sails in order to move boats?

Is anyone here familiar enough with the Newton digitized manuscripts collection, in order to offer a possible answer?

What kind of theory inspiring, natural phenomenon (besides gravity) or historic contraptions, could have been involved in his thought process of discovering the 2nd law of motion?

 

[Klystron]

I have not read Newton for many years. The last read was probably "Optiks"in English; then some new biographies. I imagine you are aware that the principal mode of ground transport in Newton's time was a horse drawn carriage for humans and light cargo and horse and ox carts for cartage.

One or two people could ride a horse at varied gaits with regular rest stops.

 

[roineust]

I have not read Newton for many years. The last read was probably "Optiks"in English; then some new biographies. I imagine you are aware that the principal mode of ground transport in Newton's time was a horse drawn carriage for humans and light cargo and horse and ox carts for cartage.

But how can constant force and acceleration be measured objectively, using a living horse? Could pulleys be involved?

 

[Klystron]

But how can constant force and acceleration be measured objectively, using a living horse? Could pulleys be involved?

How would you approach the experiment? You have accurate clocks and watches but not photographs.

 

[roineust]

How would you approach the experiment? You have accurate clocks and watches but not photographs.

How would i approach the problem with modern equipment?

 

[Klystron]

How would i approach the problem with modern equipment?

Google video of some of the first "moving pictures" late 19th and early 20th C.

One scientist "proved" a galloping horse lifts all four feet from the turf at some point. Others measured time intervals of moving horses and horse carts. Film from modern horse races should answer your questions. Look also for "surrey" races; an open horse cart used for transport and racing.

https://en.wikipedia.org/wiki/Surrey_(carriage)

 

[PeroK]

What kind of theory inspiring historic contraptions, could have been involved in his thought process of discovering the 1st law of motion?

The first law states that a body will remain at rest or continue in uniform motion in a straight line unless acted upon by an external force. I can't see how a mechanical contraption would inspire that insight.

 

[roineust]

The first law states that a body will remain at rest or continue in uniform motion in a straight line unless acted upon by an external force. I can't see how a mechanical contraption would inspire that insight.

On the other hand, i think that gravity might inspire that insight only in one direction (towards ground), if you don't look for other phenomenon or consider looking on stars and planets movement, in the context of gravity. And other phenomenon which do not appear in outer space, might be found in the principles according to mechanical contraptions work.

But the second law is more generalized, than to be relating to a case of a force acting only in one direction.

Was Newton inspired by or thinking of planet and star movements as a result of gravity force, when discovering the 2st law of motion?

 

[PeroK]

But the first law is more generalized, than to be relating to a case of a force acting only in one direction.

The first law tells you what happens in the absence of external force.

 

[roineust]

The first law tells you what happens in the absence of external force.

Yes, i was mixing by mistake the 1st and 2nd law.
Now i think i have a better intuition about the 1st law of motion: Looking at heavy objects moving over ice might be sufficient.

My whole question is now turned exactly as it was phrased, towards the 2nd law of motion:
What inspired Newton besides gravity, to generalize the 2nd law of motion, to work in all directions and not only in the direction of earth?

 

[sysprog]

Yes, i was mixing by mistake the 1st and 2nd law.
Now i think i have a better intuition about the 1st law of motion: Looking at objects moving over ice or flying horizontally in the air might be sufficient.

My whole question is now turned exactly as it was phrased, towards the 2nd law of motion:
What inspired Newton besides gravity, to generalize the 2nd law of motion, to work in all directions and not only in the direction of earth?

I think that you should go back and rethink and recast your question -- you can't just say oh I meant the second not the first so just swap in second instead of first -- the second law is more complicated.

https://www.grc.nasa.gov/WWW/k-12/airplane/Newton2

 

[roineust]

I think that you should go back and rethink and recast your question -- you can't just say oh I meant the second not the first so just swap in second instead of first -- the second law is more complicated.

My mistake, if you think that i should re-post relating to the 2nd law of motion instead of the 1st law of motion, i will. Please let me know if you think i should re-post.

P.S.
I have changed the original post, my mistake from the very beginning, sorry.

 

[sysprog]

My mistake, if you think that i should re-post relating to the 2nd law of motion instead of the 1st law of motion, i will.
Please let me know if you think i should re-post.

I think that you should rethink the matter, then recast your question, then post it. I added a NASA page link in an edit to my post. I think that if you read that material, maybe that might help you in your rethinking.

 

[Lnewqban]

... What kind of theory inspiring, natural phenomenon (besides gravity) or historic contraptions, could have been involved in his thought process of discovering the 2nd law of motion?

"If I have seen further than others, it is by standing upon the shoulders of giants." - Isaac Newton

He had previously studied books written by Copernicus, Galileo, Kepler, Descartes and Huygens.

Copied from
https://en.wikipedia.org/wiki/Philosophiæ_Naturalis_Principia_Mathematica#Historical_context

"In the 1660s Newton studied the motion of colliding bodies, and deduced that the centre of mass of two colliding bodies remains in uniform motion. Surviving manuscripts of the 1660s also show Newton's interest in planetary motion and that by 1669 he had shown, for a circular case of planetary motion, that the force he called "endeavour to recede" (now called centrifugal force) had an inverse-square relation with distance from the center. After his 1679–1680 correspondence with Hooke, described below, Newton adopted the language of inward or centripetal force. According to Newton scholar J. Bruce Brackenridge, although much has been made of the change in language and difference of point of view, as between centrifugal or centripetal forces, the actual computations and proofs remained the same either way. They also involved the combination of tangential and radial displacements, which Newton was making in the 1660s. The difference between the centrifugal and centripetal points of view, though a significant change of perspective, did not change the analysis. Newton also clearly expressed the concept of linear inertia in the 1660s: for this Newton was indebted to Descartes' work published 1644."

 

[roineust]

"If I have seen further than others, it is by standing upon the shoulders of giants." - Isaac Newton

He had previously studied books written by Copernicus, Galileo, Kepler, Descartes and Huygens.

Copied from
https://en.wikipedia.org/wiki/Philosophiæ_Naturalis_Principia_Mathematica#Historical_context

"In the 1660s Newton studied the motion of colliding bodies, and deduced that the centre of mass of two colliding bodies remains in uniform motion. Surviving manuscripts of the 1660s also show Newton's interest in planetary motion and that by 1669 he had shown, for a circular case of planetary motion, that the force he called "endeavour to recede" (now called centrifugal force) had an inverse-square relation with distance from the center. After his 1679–1680 correspondence with Hooke, described below, Newton adopted the language of inward or centripetal force. According to Newton scholar J. Bruce Brackenridge, although much has been made of the change in language and difference of point of view, as between centrifugal or centripetal forces, the actual computations and proofs remained the same either way. They also involved the combination of tangential and radial displacements, which Newton was making in the 1660s. The difference between the centrifugal and centripetal points of view, though a significant change of perspective, did not change the analysis. Newton also clearly expressed the concept of linear inertia in the 1660s: for this Newton was indebted to Descartes' work published 1644."

When Newton discovered his 2nd law of motion, was that the first time that there was an understanding that an apple falling from the tree in a straight line and the planets elliptical orbits, are the result of the same force acting or was it understood already before Newton, but not yet put into a mathematical formula?

What you are saying is, that the process of discovering Newtons 2nd law of motion, was not a process of comparing more than one natural phenomenon, that occur here on earth, such as a falling apple and say the rate of a sail-boat accelerating at constant wind speed, but a process of comparing a single phenomenon on earth, namely the fall of objects to the ground, with the planetary movements?

According to the way that i understand that history of physics/science is commonly told, there was a very important question that scientists tried to solve before Newton and it was the question asking if the planets are moving around the sun or is it the sun and planets that are moving around the Earth and what is the reason and most exact description for that planetary movement.

But the historical relation of this astronomical question to the falling apple is not clear to me, was it an obvious relation by the time of Newton (between the apple and the planetary movement) or was that relation itself a big part of his discovery, in addition to formalizing it as the 2nd law of motion?

I will try to make my question as simple as possible in another way: Out of the following options, what was the correct history of the discovery of the 2nd law of motion:

1. Apple fall --> Same as sail-boat--> or same as other Earth phenomenon--> F=ma --> Planetary movements abide.

2. According to what law planetary movements occur --> F=ma --> Apple fall abide --> other Earth phenomenon abide.

3. Apple falls here on Earth in straight line, don't yet have an equation for that --> Planets move in outer space in elliptical trajectories, don't yet have an equation for that --> Eureka! of course apples here and planets out there are exactly the same thing!--> F=ma

What i am saying in this reply, is that option no.3 seems to me the less plausible option, but i might be wrong and then might want to ask for some clarifications and for sure, there might be other options i did not think of.

 

[Klystron]

Returning for a moment to your first question, Isaac Newton kept and had access to a variety of 17th C. standard weights, scales and measures particularly for his positions at university and the government mint. His calibrated weights also included metal balls, pendulums and 'plumb bobs'; any or all of these devices could be used in experiments.

At least one biography mentions bills of lading that list laboratory equipment transported during a plague evacuation using horse coaches from university to Newton's private home where he continued work during quarantines.

Various pendulum contraptions have been used to measure and verify terrestrial motions before and after Newton's time along with inclined planes and rolling balls.