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Explanation of Overview of Gravity and Gravitation by Ron Kurtus - Succeed in Understanding Physics. Also refer to Isaac Newton, matter, attraction, force, mass, gravity, Einstein, relativity, dark matter, physical science, School for Champions. Copyright © Restrictions
Overview of Gravity and Gravitation
by Ron Kurtus (revised 26 November 2010)
Gravity and gravitation are fascinating subjects that affect us all. They are also important in the study of Physics and Astronomy.
We experience gravity in our everyday lives, since it is the attraction of objects—including our own bodies—toward the Earth. Falling objects provide a good subject for scientific measurements and experiments.
Beyond gravity is gravitation, which is the attraction of objects of mass toward each other. When objects are relatively close to the Earth, gravitation can be approximated as gravity. There are three major theories of what causes gravitation.
Gravity and gravitation equations have a number of uses and applications.
Questions you may have include:
- What is gravity?
- What is gravitation?
- What are their applications?
This lesson will answer those questions.
Useful tool: Metric-English Conversion
Gravity
Gravity is a force that attracts objects toward the Earth. The acceleration due to gravity constant is an approximation from the gravitation equation. The force of gravity is measured as the weight of an object.
An important concept that the acceleration due to gravity is considered constant near the Earth, such that all objects fall at the same rate. Also, horizontal motion is independent of the force of gravity.
Starting with the acceleration due to gravity constant, you can derive of gravity equations for the velocity, displacement and time that apply to objects dropped, thrown downward or projected upward. These equations allow you to verify the laws of gravity, as well as to apply them to predict such things as the displacement an artillery shell will travel and the relationship of work and gravity.
(See Overview of Force of Gravity to start the lessons on gravity.)
Gravitation
Gravitation is the attraction between objects because of their mass. There are three major theories of what causes gravitation: Newton’s Law of Universal Gravitation, the General Relativity Theory of Gravitation and the Quantum Theory of Gravitation. These theories are somewhat at odds with each other. There is also the question of the effect of dark matter on gravitation.
In an efforts to resolve the differences in the theories, gravitation was first compared with electromagnetic forces and then added to the list of Fundamental Forces.
The Universal Gravitational Equation provides the force of attraction between two objects. The Cavendish Experiment was used to measure the equation's gravitational constant.
Using the Universal Gravitational Equation, you can determine such things as the initial velocity required for an object to escape the gravitational pull of the Earth, Sun or other celestial bodies.
There are numerous applications of these concepts and various gravitation equations.
(See Overview of Gravitation for more about this subject.)
Applications of gravity and gravitation
There are numerous applications from the gravity and gravitation concepts and equations.
Gravity applications
Applications of gravity concepts and equations include how you can:
Determine the final energy and velocity of a falling object
Predict the displacement a projectile travels before it lands
Calculate the velocity needed to send a projectile into space
Create artificial gravity
Determine how much work gravity can do
Determine how much work is required to lift an object against gravity
See how the center of gravity of an object can be used
Gravitation applications
Applications of gravitation concepts and equations include how you can:
Measure the gravitational force between two objects
Find the center of mass of an object
Establish a circular gravitational orbit
Measure the length of year for objects in orbit
Understand how gravitation causes tides on Earth
Measure the gravitational escape velocity
Summary
Gravity is the attraction of objects toward the Earth, such that all objects fall at the same rate. Equations for velocity, displacement and time of falling objects, as well as those projected upward or downward, can be derived.
Gravitation is the attraction of objects of mass toward each other. It can be approximated as gravity for objects relatively close to the Earth. There are three major theories of what causes gravitation.
Gravity and gravitation equations have a number of uses and applications.
Always try to exceed your capabilities
Resources and references
The following resources provide information on this subject:
Websites
Acceleration due to Gravity Calculations - from Western Washington University
Force of Gravity - Universe Today Magazine
How does gravity work? - How Stuff Works
Standard gravity - Average value, as compared to variation due to position on Earth - Wikipedia
International Gravity Formula - Variation of gravity with displacement from equator - Geophysics dept. University of Oklahoma
Gravitation - NASA Worldbook
Gravitation - Wikipedia
Sir Isaac Newton: The Universal Law of Gravitation - Dept. of Physics & Astronomy University of Tennessee at Knoxville
Newton's Law of Universal Gravitation - Wikipedia
Books
Top-rated
books on Simple Gravity Science
Top-rated
books on Advanced Gravity Physics
What do you think?
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Overview of Gravity and Gravitation