Share to: share facebook share twitter share wa share telegram print page

 

Newton's cannonball

A cannon on top of a very high mountain shoots a cannonball horizontally. If the speed is low, the cannonball quickly falls back to Earth (A, B). At intermediate speeds, it will revolve around Earth along an elliptical orbit (C, D). Beyond the escape velocity, it will leave the Earth without returning (E).

Newton's cannonball was a thought experiment Isaac Newton used to hypothesize that the force of gravity was universal, and it was the key force for planetary motion. It appeared in his posthumously published 1728 work De mundi systemate (also published in English as A Treatise of the System of the World).[1][2]

Theory

In this experiment from his book (pp. 5–8),[2] Newton visualizes a stone being projected from the top of a high mountain, and that "that there is no air about the earth, or at least that it is endowed with little or no power of resisting".

As a gravitational force acts on the projectile, it will follow a different path depending on its initial velocity.

If the speed is low, it will simply fall back on Earth.

If the speed is the orbital speed at that altitude, it will go on circling around the Earth along a fixed circular orbit "and return to the mountain from which it was projected".

If the speed is higher than the orbital velocity, but not high enough to leave Earth altogether (lower than the escape velocity), it will continue revolving around Earth along an elliptical orbit.

If the speed is very high, it will leave Earth in a parabolic (at exactly escape velocity) or hyperbolic trajectory.

Source

Newton's original plan for Philosophiæ Naturalis Principia Mathematica was that it should consist of two books, the first analyzing basic laws of motion, and the second applying them to the Solar System. In order to include more material on motion in resisting media, the first book was split into two; the succeeding (now third) book, originally written in a more popular style, was rewritten to be more mathematical.[3][4] However, manuscripts of an earlier draft of this last book survived, and a version of it was published in 1728 as De mundi systemate; an English translation was also published earlier in 1728 under the name A Treatise of the System of the World.[1][2][4] The thought experiment occurs near the start of this work.

Other appearances

A photograph of page 6 from Newton's De mundi systemate (A Treatise of the System of the World), as it appears on the Voyager Golden Record

An image of the page from A Treatise of the System of the World showing Newton's diagram of this experiment was included on the Voyager Golden Record,[5] as image #111.

See also

Notes

  1. ^ a b De mundi systemate, Isaac Newton, London: J. Tonson, J. Osborn, & T. Longman, 1728.
  2. ^ a b c A Treatise of the System of the World, Isaac Newton, London: printed for F. Fayram, 1728.
  3. ^ Newton’s Philosophiae Naturalis Principia Mathematica, George Smith, 2007, Stanford Encyclopedia of Philosophy. Retrieved 14 September 2021.
  4. ^ a b Newton, Isaac; Cohen, I. Bernard (1 January 2004). A Treatise of the System of the World. Courier Corporation. ISBN 978-0-486-43880-1.
  5. ^ Sagan, Carl et al. (1978) Murmurs of Earth: The Voyager Interstellar Record. New York: Random House. ISBN 0-394-41047-5 (hardcover), ISBN 0-345-28396-1 (paperback)
Kembali kehalaman sebelumnya


Index: pl ar de en es fr it arz nl ja pt ceb sv uk vi war zh ru af ast az bg zh-min-nan bn be ca cs cy da et el eo eu fa gl ko hi hr id he ka la lv lt hu mk ms min no nn ce uz kk ro simple sk sl sr sh fi ta tt th tg azb tr ur zh-yue hy my ace als am an hyw ban bjn map-bms ba be-tarask bcl bpy bar bs br cv nv eml hif fo fy ga gd gu hak ha hsb io ig ilo ia ie os is jv kn ht ku ckb ky mrj lb lij li lmo mai mg ml zh-classical mr xmf mzn cdo mn nap new ne frr oc mhr or as pa pnb ps pms nds crh qu sa sah sco sq scn si sd szl su sw tl shn te bug vec vo wa wuu yi yo diq bat-smg zu lad kbd ang smn ab roa-rup frp arc gn av ay bh bi bo bxr cbk-zam co za dag ary se pdc dv dsb myv ext fur gv gag inh ki glk gan guw xal haw rw kbp pam csb kw km kv koi kg gom ks gcr lo lbe ltg lez nia ln jbo lg mt mi tw mwl mdf mnw nqo fj nah na nds-nl nrm nov om pi pag pap pfl pcd krc kaa ksh rm rue sm sat sc trv stq nso sn cu so srn kab roa-tara tet tpi to chr tum tk tyv udm ug vep fiu-vro vls wo xh zea ty ak bm ch ny ee ff got iu ik kl mad cr pih ami pwn pnt dz rmy rn sg st tn ss ti din chy ts kcg ve 
Prefix: a b c d e f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9