Chapter 13 Gravitation In this chapter we will explore the following topics: -Newton’s law of gravitation that describes the attractive force between two point masses and its application to extended objects -The acceleration of gravity on the surface of the earth, above it, as well as below it. -Gravitational potential energy -Kepler’s three laws on planetary motion -Satellites (orbits, energy, escape velocity) (13-1)
m1m1 m2m2 (13-2)
m1m1 m2m2 F 12 F 21 r (13-3) m1m1 m2m2 r F1F1 m2m2 m1m1
m1m1 dm r (13-4)
(13-5)
y-axis (13-6)
m1m1 m2m2 r F1F1 m2m2 m1m1 (13-7)
r m (13-8)
(13-9)
mB v = 0 m v A (13-10)
Polaris Celestial sphere Rotation Axis of the Celestial sphere earth N S Star (13-11)
(13-12)
(13-13)
(13-14)
(13-15)