What is gravitational potential energy? (article) | Khan Academy
Gravitational potential energy (GPE) is associated with an object's mass and its work one must do to lift an object some distance against a gravitational force. There is a direct relation between gravitational potential energy and the mass of an object. These relationships are expressed by the following equation: For certain springs, the amount of force is directly proportional to the amount of. Gravitational potential energy and gravitational force are different! The gravitational force only depends on the mass of an object.
This stored energy of position is referred to as potential energy. Similarly, a drawn bow is able to store energy as the result of its position.
What is gravitational potential energy?
When assuming its usual position i. Yet when its position is altered from its usual equilibrium position, the bow is able to store energy by virtue of its position.
- Gravitational potential energy (GPE)
- Potential Energy
- Gravitational Potential Energy
Potential energy is the stored energy of position possessed by an object. Gravitational Potential Energy The two examples above illustrate the two forms of potential energy to be discussed in this course - gravitational potential energy and elastic potential energy. Gravitational potential energy is the energy stored in an object as the result of its vertical position or height. The energy is stored as the result of the gravitational attraction of the Earth for the object.
The gravitational potential energy of the massive ball of a demolition machine is dependent on two variables - the mass of the ball and the height to which it is raised.Relationship Between Force and Potential Energy
There is a direct relation between gravitational potential energy and the mass of an object. More massive objects have greater gravitational potential energy. There is also a direct relation between gravitational potential energy and the height of an object. The higher that an object is elevated, the greater the gravitational potential energy. These relationships are expressed by the following equation: To determine the gravitational potential energy of an object, a zero height position must first be arbitrarily assigned.
Typically, the ground is considered to be a position of zero height.
But this is merely an arbitrarily assigned position that most people agree upon. Since many of our labs are done on tabletops, it is often customary to assign the tabletop to be the zero height position.
Again this is merely arbitrary.
Work and energy
If the tabletop is the zero position, then the potential energy of an object is based upon its height relative to the tabletop.
To get around this, astronomers use one of two units: Of the two, the more intuitive to me is the light year, which is the distance a beam of light would travel in one year 9. The other unit, the parsec, is a geometric rather than physical unit.
Astronomical bodies near to us well, near in astronomical terms will appear to shift their position in the sky as the Earth moves around in its orbit. The word parsec stands for "parallax of one arc second".
Thus, an object that appears to shift by one arc second one th of one degree! For observational astronomers of the Nineteenth and early Twentieth Centuries, the parsec was a more convenient unit for professional use than the light year. One parsec [pc] is approximately 3. The nearest stars to the Earth other than the sun are a bit more than one parsec away. The edge of the Milky Way is several thousand parsecs away — several kiloparsecs [kpc].
Cosmic distances, like those between galaxies, are measured in millions of parsecs or megaparsecs [Mpc]. This is the unit that Hubble used in his work.
I have included his original data in the section of this book entitled Curve Fitting. You can analyze the data yourself if you wish.
Gravitational Potential Energy – The Physics Hypertextbook
The interesting thing about this value is that it is now universally recognized as terribly wrong. Distance measurements of extra galactic bodies in Hubble's era were later found to be seriously flawed.
Still, the theory turned out to be right even if the data used to derive it were all undervalued. Determination of H has progressed slowly but surely since the early Twentieth Century and the constant has gone through several revisions.