Rev. 1 REVIEW SHEET #10: Gravitation Newton’s Law of Gravitation: Every particle of matter in the universe attracts every other particle of matter with a force that is directly proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them. 1 2 2 12 g Gm m F r = the constant G=6.67x10-11 N*m 2 /kg 2 The direction of F g is along the straight line that joins the two masses. If a mass m is subject to more than one gravitational force, the total gravitational force is the vector sum of all the individual gravitational forces that act on m. The weight of a body of mass m is the total gravitational force exerted on the body by all other bodies in the universe. For a body near the surface of the earth, the weight of the body is considered to be just the gravitational force that the earth exerts on the body: 2 E E g mg Gm m w F R = = = Hence 2 E E Gm g R = (m E = earth’s mass = 5.98x10 24 kg; R E = earth’s mean radius = 6.38x10
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This note was uploaded on 09/11/2011 for the course PHYS 0174 taught by Professor Kohler during the Spring '08 term at Pittsburgh.