# Gravitation

## Gravitational Potential Energy

Gravitational Potential Energy We discussed the gravitational potential energy of a particle-Earth system. We were careful to keep the particle near Earth’s surface, so that we could regard the gravitational force as constant. We then chose some reference configuration of the system as having a  gravitational. Here, we broaden our view and consider the gravitational potential energy U …

## Sample Problem

Sample Problem In Pole 10 Pole, an early science fiction story by George Griffith. three explorers attempt to travel by capsule through a naturally formed (and, of course, fictional) tunnel directly from the south pole to the north pole . According to the story, as the capsule approaches Earth’s center, the gravitational force on the explorers becomes alarmingly. SOLUTION: Newton’s …

## Gravitation Inside Earth

Gravitation Inside Earth Caution: This statement does not mean that the gravitational forces on the particle from the various elements of the shell magically disappear. Rather, it means that the sum of the force vectors on the particle from all the elements is zero. If the density of Earth were uniform, the gravitational force acting on a …

## Sample Problem

Sample Problem (a) An astronaut whose height h is 1.70 m floats feet down in an orbiting space shuttle. SOLUTION: One Key Idea here is that we can approximate Earth as a uniform sphere of mass M. (b) If the astronaut is now feet down at the same orbital radius r of 6.77 X 106 m about a …

## Gravitation Near Earth’s Surface

Gravitation Near Earth’s Surface Let us assume that Earth is a uniform sphere of mass M. The magnitude of the gravitational force from Earth on.a particle of mass m, located outside Earth a distance I’ from Earth’s center. If the particle is released will fall toward the center of Earth. as a result of the gravitational force. L …

## PROBLEM SOLVING TACTICS

PROBLEM SOLVING TACTICS Tactic 1: Drawing Gravitational Force Vectors When you are given a diagram of particles, such as ,and asked to find the net gravitational force on one of them, you should usually draw a free-body diagram showing only the particle of concern and the force. Tactic 2: Simplifying a Sum of Forces with Symmetry In Sample …

## Sample Problem

Sample Problem Shows an arrangement of three particles, particle I having mass m, = 6.0 kg and particles 2 and 3 having mass nl2 = nil = 4.0 kg, and with distance a = 2.0 cm. SOLUTION: One Key Idea here is that. because we have particles, the magnitude of the gravitational force on particle I due to …

## Gravitation and the Principle of Superposition

Gravitation and the Principle of Superposition Given a group of particles, we find the net (or resultant) gravitational force on any one of them from the others by using the principle of superposition. This is a general principle that says a net effect is the sum of the individual effects. Here, the principle means that we first compute the …

## Newton’s Law of Gravitation

Newton’s Law of Gravitation Physicists like to study seemingly unrelated phenomena to show that a relationship can be found if they are examined closely enough. This search for unification has been going on for centuries. In 1665, the 23-year-old Isaac Newton made a basic contribution to physics when he showed that the force that holds the Moon in …

## The World and the Gravitational Force

The World and the Gravitational Force The drawing that opens this chapter shows our view of the Milky Way galaxy. We are near the edge of the disk of the galaxy, about 26 000 light-years (2.5 x 1020 m) from its center, which in the drawing lies in the star collection known as Sagittarius, Our galaxy is a …