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Gravity

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-80

2025-11-04

402

While the term gravitation is applied to the universal attraction existing between particles of matter, the more restricted term gravity is applied to the attraction that exists between the earth and bodies upon or near its surface. The law given above applies to gravity, provided that d is measured in a straight line from the center of the earth to the center of mass of the body. This line is called a vertical line, or sometimes a pluть line (from the Latin word plumbum, which means "lead "), as vertical lines are frequently determined by suspending a mass of lead, the plumb bob, at the end of a cord (Fig. 1).

Fig. 1