PHYS 1010Q Lecture Notes - Lecture 10: Centripetal Force
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Document Summary
Newton"s gravity, newton"s law of universal gravitation, g decreases with elevation. A car drives about a track at speed v. if the frictional force is 7000 n. then how fast is the car moving? m=1000kg. Newton knew that there must be an attractive force on the moon to keep it in the circular orbit around the earth. This force was a centripetal force in that it must point toward the center of the circular path, i. e. toward the earth. Newton also knew the radius of the moon"s orbit about the earth (r em=3. 8 x 10^8 m) and the period of the moon"s orbit (t m= 27. 3 days= 2. 36 x 10^6 s) To test his calculation of the acceleration, newton compared the fall of an apple to the fall of the moon. He realized that the moon fell in the sense that it falls away from the straight line that it would travel if there were no forces acting on it.
