PH-UY 1013 Lecture Notes - Lecture 4: Junkers J 1, Net Force, Acceleration
Document Summary
Universal law of gravitation: gravity is always attraction between two masses. Masses of sun, moon, earth on ref table. Forces on two bodies are equal/opposite (3rd law: determines the magnitude of gravity for any two objects. G is the universal gravitational constant, 6. 67x10-11 m3/kgs2. Simplifies to fg = mg for near earth"s surface. Circular motion: object moves in a circle with constant speed and constant radius, period and frequency. T is the period of time for one revolution f is how frequently the object revolves, how many revolutions per second. T = 1/f; f = 1/t: tangential velocity. The velocity of the object tangent to the circle vt = distance/time = circumference/period = 2 r/t = 2 rf. The magnitude of velocity, or speed, does not change, but direction does: centripetal acceleration. Objects in circular motion are accelerating, their acceleration is center seeking, or centripetal. D. 3. ac = v2/r, where v is the tangential velocity.
