Gravitational Force
Newton's Law of Universal Gravitation
Apples had a significant contribution to the discovery of gravitation. The
English physicist Isaac Newton
(1642-1727) introduced the term
"gravity" after he saw an apple falling onto the ground in his garden.
"Gravity" is the force of attraction exerted by the earth on an object.
The moon orbits around the earth because of gravity too. Newton later proposed that gravity was just a particular case of gravitation. Every mass in the universe attracts every other mass. This is the main idea of
Newton's Law of Universal
Gravitation.
A portrait of Issac Newton.
Courtesy of AIP Emilio Segre Visual
Archives, W.F. Meggers Collection.
The law was published in Newton's famous work, the Principia
("Mathematical Principles of Natural
Knowledge") in 1687. It states that every particle in the universe exerts a force on every other particle along the line joining their centers. The magnitude of the force is directly proportional to the product of the masses of the two particles, and inversely proportional to the square of the distances between them.
In mathematical terms:
By team C007571, ThinkQuest2000. where and are the masses of the two particles, r is the distance between the two masses, F is the gravitational force between them, and
G is the universal gravitational constant, .
The above equation only calculates the gravitational force of the simplest case between two particles. What if there are more than two? In that case, we calculate the resultant gravitational force on a particle by finding the vector sum of all the gravitational forces acting on it:
By adding the unit vector to the equation, F now processes a direction!
Interactively test the effects of gravitation on planets!
Newton derived the relation in such a way that F is proportional to m because the force on a falling body
(remember the apple?) is directly proportional to its mass by Newton's
2nd law of motion: F = ma, so F is proportional to m . When the earth exerts a
Apples had a significant contribution to the discovery of gravitation. The
English physicist Isaac Newton
(1642-1727) introduced the term
"gravity" after he saw an apple falling onto the ground in his garden.
"Gravity" is the force of attraction exerted by the earth on an object.
The moon orbits around the earth because of gravity too. Newton later proposed that gravity was just a particular case of gravitation. Every mass in the universe attracts every other mass. This is the main idea of
Newton's Law of Universal
Gravitation.
A portrait of Issac Newton.
Courtesy of AIP Emilio Segre Visual
Archives, W.F. Meggers Collection.
The law was published in Newton's famous work, the Principia
("Mathematical Principles of Natural
Knowledge") in 1687. It states that every particle in the universe exerts a force on every other particle along the line joining their centers. The magnitude of the force is directly proportional to the product of the masses of the two particles, and inversely proportional to the square of the distances between them.
In mathematical terms:
By team C007571, ThinkQuest2000. where and are the masses of the two particles, r is the distance between the two masses, F is the gravitational force between them, and
G is the universal gravitational constant, .
The above equation only calculates the gravitational force of the simplest case between two particles. What if there are more than two? In that case, we calculate the resultant gravitational force on a particle by finding the vector sum of all the gravitational forces acting on it:
By adding the unit vector to the equation, F now processes a direction!
Interactively test the effects of gravitation on planets!
Newton derived the relation in such a way that F is proportional to m because the force on a falling body
(remember the apple?) is directly proportional to its mass by Newton's
2nd law of motion: F = ma, so F is proportional to m . When the earth exerts a