14

The Law of Gravity

14.1 Newton’s Law of Universal Gravitationevery particle in the Universe attracts every other particle with a force

that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Properties of the gravitational force

14.2 Measuring the Gravitational Constant

• The universal gravitational constant G was measured in an important experiment by Henry Cavendish (1731–1810) in 1798.

EXAMPLE : Billiards, Anyone?

Solution

14.3 Free-Fall Acceleration and the Gravitational Force

14.4 Kepler’s Laws

14.5 The Law of Gravity and the Motion of Planets

Kepler’s Third Law

Kepler’s Second Law and Conservation of Angular Momentum

the radius vector from the Sun to a planet sweeps out equal areas in equal time intervals.

14.6 The Gravitational Field

14.7 Gravitational Potential Energy• the gravitational force is conservative.

• a central force is always directed along one of the radial segments, therefore, the work done by F along any radial segment is

• any central force is conservative

Three interacting particles

14.8 Energy Considerations in Planetary and Satellite Motion

Escape Speed

14.9 (Optional )The Gravitational Force Between an Extended Object and a Particle

14.10 The Gravitational Force Between a Particle and a Spherical Mass