PHYS 2101 Lecture : Lecture22
Document Summary
Isaac newton (1687) : what keeps the moon in a nearly circular orbit about the earth: circular orbit: must be accelerating, and therefore must be a force on the moon. Gravity: the same gravitational force that attracts the us to the earth holds the moon in orbit. In fact, there is an attractive gravitational force between all pairs of objects: force between two point masses depends on their separation r and their masses: 2 r 2 m1 and m2 are masses and r is distance between them and G = 6. 67 "10#11 n $ m 2 / kg 2. Imagine i re a gun horizontally on the earth, and pretend nothing gets in the way (i. e. we go to the top of mt. The distance the bullet travels increases if the bullet speed increases : as we re bullets faster and faster, they travel further , but the earth is a sphere! (approximately) Bullet trajectories actually wrap around the earth.
