Although gravitation is no longer on the AAMC's list for the new MCAT, the comparison and contrast of gravitational force with electrostatic force is so helpful to understanding that the subject remains as a supplemental chapter in this course. Both electrostatic force and gravitation are inverse square law forces. There are many important similarities in problem solving between gravitation and the electrostatic force. Learning a bit about gravitation will lay some important groundwork for understanding and modelling force and energy relationships. For many students, this will make electrostatics more accessible.

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**Gravitation Cards****Gravitation Images****Question Drill for Gravitation**

Conceptual Vocabulary Self-Test**Basic Terms Crossword Puzzle****Basic Puzzle Solution**

Conceptual Vocabulary for Gravitation

Gravitation

Gravitation is a natural phenomenon by which all objects with mass attract each other.

Gravitation is a natural phenomenon by which all objects with mass attract each other.

Tide

Tides are the cyclic rising and falling of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans.

Tides are the cyclic rising and falling of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans.

Center of mass

The center of mass of a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated.

The center of mass of a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated.

Gravitational field

The gravitational field around a single particle in classical mechanics is a vector field pointing directly towards the particle giving the magnitude of the force per unit mass for the array of points in space.

The gravitational field around a single particle in classical mechanics is a vector field pointing directly towards the particle giving the magnitude of the force per unit mass for the array of points in space.

Orbit

A orbit is the path that an object makes around another object while under the influence of a centripetal force such as gravity.

A orbit is the path that an object makes around another object while under the influence of a centripetal force such as gravity.

Escape velocity

Escape velocity is the speed where the kinetic energy of an object is equal in magnitude to its potential energy in a gravitational field.

Escape velocity is the speed where the kinetic energy of an object is equal in magnitude to its potential energy in a gravitational field.

General relativity

General relativity is the geometrical theory of gravitation published by Albert Einstein in 1915-16 unifying special relativity and Newton's law of universal gravitation.

General relativity is the geometrical theory of gravitation published by Albert Einstein in 1915-16 unifying special relativity and Newton's law of universal gravitation.

Standard gravity

Standard gravity is the nominal acceleration due to gravity at the Earth's surface at sea level.

Standard gravity is the nominal acceleration due to gravity at the Earth's surface at sea level.

Gravitational binding energy

The gravitational binding energy of an object consisting of loose material, held together by gravity alone, is the amount of energy required to pull all of the material apart, to infinity.

The gravitational binding energy of an object consisting of loose material, held together by gravity alone, is the amount of energy required to pull all of the material apart, to infinity.

Inverse-square law

An inverse-square law is any physical law stating that some physical quantity or strength decreases proportional to the square of the distance from the source of that physical quantity.

An inverse-square law is any physical law stating that some physical quantity or strength decreases proportional to the square of the distance from the source of that physical quantity.

Cavendish experiment

The Cavendish experiment, performed in 1797 - 1798, was the first experiment to measure the force of gravity between laboratory masses.

The Cavendish experiment, performed in 1797 - 1798, was the first experiment to measure the force of gravity between laboratory masses.

Orbital period

The orbital period is the time it takes a planet (or another object) to make one full orbit.

The orbital period is the time it takes a planet (or another object) to make one full orbit.

Geosynchronous satellite

A geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time.

A geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time.

Geosynchronous orbit

A geosynchronous orbit is an orbit around the Earth with an orbital period matching the Earth's sidereal rotation period.

A geosynchronous orbit is an orbit around the Earth with an orbital period matching the Earth's sidereal rotation period.

Geostationary orbit

A geostationary orbit is a geosynchronous orbit directly above the Earth's equator, with orbital eccentricity of zero. From the ground, such an object appears motionless in the sky.

A geostationary orbit is a geosynchronous orbit directly above the Earth's equator, with orbital eccentricity of zero. From the ground, such an object appears motionless in the sky.

Circular orbit

A circular orbit is an elliptic orbit with the eccentricity equal to zero.

A circular orbit is an elliptic orbit with the eccentricity equal to zero.

Ellipse

An ellipse is the locus of points on a plane where the sum of the distances from any point on the curve to two fixed points is constant.

An ellipse is the locus of points on a plane where the sum of the distances from any point on the curve to two fixed points is constant.

Astronomical unit

The astronomical unit is a unit of length nearly equal to the semi-major axis of Earth's orbit around the Sun.

The astronomical unit is a unit of length nearly equal to the semi-major axis of Earth's orbit around the Sun.

Perigee

Perigee is the point at which an object in orbit around the Earth makes its closest approach to the Earth.

Perigee is the point at which an object in orbit around the Earth makes its closest approach to the Earth.

Kepler's laws of planetary motion

Johannes Kepler (1571 - 1630) was a German mathematician whose primary contributions to astronomy and astrophysics were his three laws of planetary motion.

Johannes Kepler (1571 - 1630) was a German mathematician whose primary contributions to astronomy and astrophysics were his three laws of planetary motion.

Perturbation

Perturbation is a term used in astronomy to describe alterations to an object's orbit caused by gravitational interactions with other bodies.

Perturbation is a term used in astronomy to describe alterations to an object's orbit caused by gravitational interactions with other bodies.

Apsis

An apsis is the point of greatest or least distance of the elliptical orbit of an astronomical object from its center of attraction.

An apsis is the point of greatest or least distance of the elliptical orbit of an astronomical object from its center of attraction.

Heliocentrism

Heliocentrism is the theory that the sun is at the centre of the Universe and/or the Solar System.

Heliocentrism is the theory that the sun is at the centre of the Universe and/or the Solar System.

Low Earth orbit

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth's surface up to an altitude of 2,000 km.

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth's surface up to an altitude of 2,000 km.

Specific orbital energy

The specific orbital energy of an orbiting body traveling through space is the sum of its potential energy and kinetic energy per unit mass.

The specific orbital energy of an orbiting body traveling through space is the sum of its potential energy and kinetic energy per unit mass.

Standard gravitational parameter

The standard gravitational parameter of a celestial body is the product of the gravitational constant and the mass.

The standard gravitational parameter of a celestial body is the product of the gravitational constant and the mass.