Forces in Space

Vocabulary flashcards covering gravity, universal gravitation, mass, distance, weight, inertia, Newton's First Law, and orbital motion from the lecture notes.

Gravity

The force of attraction between any two objects.

Law of Universal Gravitation

Every object in the universe attracts every other object; the strength depends on their masses and the distance between them.

Mass

The amount of matter in an object; greater mass increases gravity and inertia.

Distance

The separation between two objects; gravity decreases as distance increases.

Weight

The force of gravity acting on a mass; weight varies with gravity (e.g., less on the Moon than on Earth).

Inertia

The resistance of an object to changes in its motion; more mass means greater inertia.

Newton's First Law (Inertia)

An object at rest stays at rest and an object in motion stays in motion unless acted on by an outside force.

Orbit

The path of a body around another body, kept in check by gravity and inertia.

Satellite

An object in orbit around a planet.

Moon vs Earth Weight

Weight is less on the Moon than on Earth because gravity is weaker there.

Gravity and Orbital Motion

Gravity keeps planets in orbit around the Sun; inertia keeps them moving.

Earth's Orbit (Sun's Gravity)

The Sun's gravity pulls Earth toward it while Earth's forward motion (inertia) keeps it moving, producing an orbit.