Kepler's Laws of Planetary Motion and Periodic Motion

A set of vocabulary flashcards defining key terms, historical figures, laws of planetary motion, and concepts of periodic and harmonic motion.

Tycho Brahe

An astronomer who collected detailed observations and measurements of planetary positions.

Johannes Kepler

An astronomer who studied Tycho Brahe's observations to develop three laws describing planetary motion around the Sun.

Isaac Newton

The scientist who demonstrated that Kepler's laws can be explained by his Law of Universal Gravitation.

Ellipse

An oval-shaped path with two foci; the geometric shape followed by planets orbiting the Sun.

Perihelion

The point in an elliptical orbit where a planet is closest to the Sun, moving at its fastest speed.

Aphelion

The point in an elliptical orbit where a planet is farthest from the Sun, moving at its slowest speed.

Law of Orbits (Kepler's First Law)

The law stating that planets move in elliptical orbits with the Sun located at one of the two foci.

Law of Areas (Kepler's Second Law)

The law stating that an imaginary line connecting a planet to the Sun sweeps out equal areas in equal time intervals.

Law of Periods (Kepler's Third Law)

The law stating that the squares of the periods of the planets are proportional to the cubes of their average distances from the Sun ($T^2 \propto r^3$).

Period ($T$)

The time required for an object or planet to complete one full revolution, vibration, or oscillation.

Universal Gravitational Constant ($G$)

The constant of proportionality in Newton's gravitational force equation.

Periodic Motion

Motion in which an object repeatedly moves back and forth over the same path at regular intervals.

Simple Harmonic Motion (SHM)

An oscillatory motion experienced by an object displaced from equilibrium, where its acceleration is directly proportional to its displacement and directed opposite to it.

Amplitude ($A$)

The maximum displacement attained by an oscillating body on either side of its equilibrium position.

Frequency

The total number of vibrations or oscillations performed per unit time.

Simple Pendulum

A pendulum system consisting of a bob of relatively large mass hanging from a string with negligible mass.

Physical Pendulum

An extended real object that oscillates back and forth about an axis under a restoring torque, with its mass distributed throughout the body.

Torsion Balance

A system where a disk or body is displaced such that a restoring torque produces angular harmonic motion around an axis perpendicular to its plane.