# Thread: Three Laws and an apple

1. ## Three Laws and an apple

It is a general question .

Can anybody guess , how Newton could develope his three Laws of Motion from an apple ?

2. Newton himself often told the story that he was inspired to formulate his theory of gravitation by watching the fall of an apple from a tree.[103] Although it has been said that the apple story is a myth and that he did not arrive at his theory of gravity in any single moment,[104] acquaintances of Newton (such as William Stukeley, whose manuscript account, published in 1752, has been made available by the Royal Society)[105] do in fact confirm the incident, though not the cartoon version that the apple actually hit Newton's head. Stukeley recorded in his Memoirs of Sir Isaac Newton's Life a conversation with Newton in Kensington on 15 April 1726:[106]

... We went into the garden, & drank tea under the shade of some appletrees, only he, & myself. amidst other discourse, he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. "why should that apple always descend perpendicularly to the ground," thought he to him self: occasion'd by the fall of an apple, as he sat in a comtemplative mood: "why should it not go sideways, or upwards? but constantly to the earths centre? assuredly, the reason is, that the earth draws it. there must be a drawing power in matter. & the sum of the drawing power in the matter of the earth must be in the earths centre, not in any side of the earth. therefore dos this apple fall perpendicularly, or toward the centre. if matter thus draws matter; it must be in proportion of its quantity. therefore the apple draws the earth, as well as the earth draws the apple."

John Conduitt, Newton's assistant at the Royal Mint and husband of Newton's niece, also described the event when he wrote about Newton's life:[107]

In the year 1666 he retired again from Cambridge to his mother in Lincolnshire. Whilst he was pensively meandering in a garden it came into his thought that the power of gravity (which brought an apple from a tree to the ground) was not limited to a certain distance from earth, but that this power must extend much further than was usually thought. Why not as high as the Moon said he to himself & if so, that must influence her motion & perhaps retain her in her orbit, whereupon he fell a calculating what would be the effect of that supposition.

http://en.wikipedia.org/wiki/Isaac_Newton

3. Newton didn't develop his laws of motion from an apple. The law of gravity is a different thing.

4. Originally Posted by hansda
It is a general question .

Can anybody guess , how Newton could develope his three Laws of Motion from an apple ?
He ate it. That gave him some of the nutrients necessary to think about stuff.

5. Originally Posted by Buddha12
Newton himself often told the story that he was inspired to formulate his theory of gravitation by watching the fall of an apple from a tree.[103] Although it has been said that the apple story is a myth and that he did not arrive at his theory of gravity in any single moment,[104] acquaintances of Newton (such as William Stukeley, whose manuscript account, published in 1752, has been made available by the Royal Society)[105] do in fact confirm the incident, though not the cartoon version that the apple actually hit Newton's head. Stukeley recorded in his Memoirs of Sir Isaac Newton's Life a conversation with Newton in Kensington on 15 April 1726:[106]
I believe gravity corresponds to the Second Law of Motion . How you can co-relate First Law and Third Law of Motion with an apple ?

6. Originally Posted by James R
Newton didn't develop his laws of motion from an apple. The law of gravity is a different thing.
He might have got the inspiration from an apple to develope these three Laws of Motion . I find there is some co-relation between these three Laws and an apple . I wanted others to guess about this co-relation .

7. Originally Posted by wynn
He ate it. That gave him some of the nutrients necessary to think about stuff.
In addition to nutrients , the apple gave Newton some ideas to think about stuff . Can you guess about these ideas ?

8. Originally Posted by hansda
I believe gravity corresponds to the Second Law of Motion.
Then you believe wrong.

How you can co-relate First Law and Third Law of Motion with an apple ?
Simple.

An apple will remain travelling at constant velocity (which may be zero) unless acted on by a force. If another object exerts a force on an apple, the apple will exert an equal and opposite force on the other object.

Originally Posted by hansda
He might have got the inspiration from an apple to develope these three Laws of Motion.
He never said he did. On the other hand, when it came to the law of gravity...

I find there is some co-relation between these three Laws and an apple. I wanted others to guess about this co-relation .
The suspense is killing me. Why don't you just tell us all?

9. Originally Posted by hansda
It is a general question .

Can anybody guess , how Newton could develope his three Laws of Motion from an apple ?
My guess is as follows :

An apple while falling from the tree to the ground , has three phases of motion .

1. First Phase - The apple is not falling . It is attached with the tree .

In this case the gravitaional force on the apple is balanced by its force of attachment with the tree . So , here the resultant vertical force on apple is zero . Thats why the apple is not falling or moving in the vertical direction .

This fact is an example of Newton's First Law of Motion .

2. Second Phase - The apple is detached from the tree and is falling vertically towards ground .

Here the apple is accelerating downwards under the force of gravity .

This is an example of Newton's Second Law of Motion .

3. Third Phase - The apple has fallen on the ground and its motion is stopped .

Here the apple makes an impact with the ground .

This is an example of action-reaction principle of Newton's Third Law of Motion .

Thus , from these three phases of motion of an apple , Newton might have got ideas to develope his Three Laws of Motion .

10. Since Newton and his biographers have written about this, why guess?

11. Originally Posted by AlexG
Since Newton and his biographers have written about this, why guess?
Can you give reference , where it was already written ?

12. Originally Posted by hansda
Can you give reference , where it was already written ?
Go read post #2

13. Originally Posted by AlexG
Go read post #2
Post #2 does not tell anything about Newton's First Law and Third Law , in relation with the apple . So , there is scope for some guess .

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