A Comprehensive System of Astronomy, Both Theoretic and Practical, with Extensive Tables of the Sun, Moon, and Planets

A Comprehensive System of Astronomy, Both Theoretic and Practical, with Extensive Tables of the Sun, Moon, and Planets

By (author) 

List price: US$32.10

Currently unavailable

Add to wishlist

AbeBooks may have this title (opens in new window).

Try AbeBooks

Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1828 edition. Excerpt: ...projectile direction. In like manner, when the body should have arrived at the points C, D, &c. it will be found at the points 1, L, &c. the extremities of the perpendiculars C/I, DL, &c. But the spaces passed over by a body falling freely by its, own weight, are as the squares of the times, by the last theorem; hence BG, CI, DL, &c."or their equals AF, AH, AK, &c. are proportional to the squares of the times; but AB, AC, AD, &c. are directly as the times; or their equals, FG, HI, KL, &c. are as the times; and consequently AF is to AH, as the square of FG is to the square of HI; and AF is to AK, as the square of FG is to the square of KL, &c.: that is, the abscissa are as the squares of their semi-ordinates, which is the characteristic property of the parabola; from what we have de livered in our conic sections. Wherefore the curve AGIL is a parabola. Q. E. D. Tnsoasm 10. GRAVITY decreases according to the square of the distance from the centre; that is, gravity is reciprocally proportional to the square of the distance from the centre. Thus if a body weigh 16lb. on the surface of the Earth: then if it be carried upwards to twice the distance from the Earth's centre it will weigh but that weight; and if it be carried to three times that distance from the centre, it will weigh but 5 of its real weight on the surface, &c. For instance let us suppose the radius of the Earth, in round-numbers, to be 4000 miles; then the gravity ofa body of 16lb. weight on the surface, is only equal of16lb. or 4lb., and ifwe suppose it to be carried upwards to the distance of 2 semi-diameters from the centre, or 8000 miles; and ifto 3 semidiameters, its gravity is only ', -''lb., or 1glb., ...show more

Product details

  • Paperback | 202 pages
  • 189 x 246 x 11mm | 372g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236908694
  • 9781236908698