Talk:Newton's cannonball

Missing points and invalid reference to the moon.
The moon follows an elliptical orbit, not a circular one as this problem describes. Additionally, it also leaves out the elliptical orbit formed when the cannonball is slower than the orbital velocity, but not slow enough to fall to the Earth (effectively the same as firing from the opposite point in the elliptical orbit shown. — Preceding unsigned comment added by Black.jeff (talk • contribs) 22:02, 10 October 2011 (UTC)


 * Remember, this cannonball is being fired from the surface of the earth, not beginning above the surface of the earth. So if it is going slower than orbital velocity, it will hit the ground somewhere rather than entering an orbit. 134.29.231.11 (talk) 21:57, 7 April 2014 (UTC)

Single Source
I've added a reference to Sir Isaac's original book. While this article only has two references, it no longer is "single sourced". If there is no objection in a week or two, I'll remove that banner/template. Jarod (talk) 13:27, 2 June 2014 (UTC)

External links modified (January 2018)
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problem
In here in the thought experience section the cannon stands on vertically not in horizontally. The Gif needs to be modified. Sorghum 14:09, 29 November 2018 (UTC)
 * That's not the cannon, it's the tower or mountain it's set on top of. Andy Dingley (talk) 14:23, 29 November 2018 (UTC)

Mistitled article?
In the version of Principia referenced in this article, there is no mention of a "cannonball" or even a "cannon". Instead, Newton describes a "stone" being "projected". One possibility is that that there is an issue with the edition of Principia. The referenced Google eBook does not have an edition number, although the date, 1728, suggests the third edition. My home version (from The Great Books) does not mention even the stone, but refers to a low-orbiting moon, so I think it must be the first edition. I would welcome some discussion about how to fix this problem. Most helpful would be some history of how the phrase "Newton's Cannonball" came about in the first place.

-- SpencerRugaber — Preceding unsigned comment added by SpencerRugaber (talk • contribs) 19:56, 17 August 2020 (UTC)
 * I tried to clarify the textual history of this thought experiment in my recent edits to the article. Spacepotato (talk) 21:31, 14 September 2021 (UTC)