Difference between revisions of "Free fall"
m (Text replacement - "http://" to "https://") |
|||
| (One intermediate revision by the same user not shown) | |||
| Line 1: | Line 1: | ||
[[File:lighterstill.jpg]][[File:Free_falling200.jpg|right|frame]] | [[File:lighterstill.jpg]][[File:Free_falling200.jpg|right|frame]] | ||
| − | *[ | + | *[https://en.wikipedia.org/wiki/20th_century 1919] |
==Definitions== | ==Definitions== | ||
*1: the condition of unrestrained [[motion]] in a [[gravitational]] field; also : such motion | *1: the condition of unrestrained [[motion]] in a [[gravitational]] field; also : such motion | ||
| − | *2a : the part of a [ | + | *2a : the part of a [https://en.wikipedia.org/wiki/Parachute_jump parachute jump] before the parachute opens |
:b : a rapid and continuing drop or decline <a free fall in stock prices> | :b : a rapid and continuing drop or decline <a free fall in stock prices> | ||
==Description== | ==Description== | ||
| − | In [ | + | In [https://en.wikipedia.org/wiki/Newtonian_physics Newtonian physics], '''free fall''' is any motion of a body where its [[weight]] is the only [[force]] acting upon it. In the [[context]] of General Relativity where [[gravitation]] is reduced to a [[space-time]] curvature, a body in ''free fall'' has no force acting on it and it moves along a [https://en.wikipedia.org/wiki/Geodesic geodesic]. The present article concerns itself with free fall in the Newtonian domain. |
An object in the technical sense of ''free fall'' may not necessarily be falling down in the usual sense of the term. An object moving upwards would not normally be considered to be falling but if it is subject to the [[force]] of [[gravity]] only, it is said to be in free fall. The [[moon]] thus is in free fall. | An object in the technical sense of ''free fall'' may not necessarily be falling down in the usual sense of the term. An object moving upwards would not normally be considered to be falling but if it is subject to the [[force]] of [[gravity]] only, it is said to be in free fall. The [[moon]] thus is in free fall. | ||
| − | In a [[uniform]] [[gravitational]] field, in the absence of any other forces, gravitation acts on each part of the [[body]] equally and this is akin to [ | + | In a [[uniform]] [[gravitational]] field, in the absence of any other forces, gravitation acts on each part of the [[body]] equally and this is akin to [https://en.wikipedia.org/wiki/Weightlessness weightlessness], a condition which also obtains when the gravitational field is zero such as when far away from any gravitating body. A body in free fall [[experiences]] "0-g". |
| − | The term "free fall" is often used more loosely than in the strict sense defined above. Thus, falling through an [[atmosphere]] without a deployed parachute, or lifting device, is also often referred to as free fall. The aerodynamic drag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching [ | + | The term "free fall" is often used more loosely than in the strict sense defined above. Thus, falling through an [[atmosphere]] without a deployed parachute, or lifting device, is also often referred to as free fall. The aerodynamic drag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching [https://en.wikipedia.org/wiki/Terminal_velocity terminal velocity] produces the sensation of the body's weight being [[supported]] on a cushion of air. [https://en.wikipedia.org/wiki/Free_fall] |
==Quote== | ==Quote== | ||
| − | It is perhaps likened to your [[journey]] ahead. You are '''free-falling''' without [[thought]] of where you shall lay your head to where you shall [[receive]] your meals. It is so [[difficult]] for mortals to release all that they are, know and have, and in the clutching of this, the [[energy]] is spent, and the [[connection]] with Father weak. It takes a [[courageous]] [[individual]] to be willing to be lost to [[become]] more. [ | + | It is perhaps likened to your [[journey]] ahead. You are '''free-falling''' without [[thought]] of where you shall lay your head to where you shall [[receive]] your meals. It is so [[difficult]] for mortals to release all that they are, know and have, and in the clutching of this, the [[energy]] is spent, and the [[connection]] with Father weak. It takes a [[courageous]] [[individual]] to be willing to be lost to [[become]] more. [https://nordan.daynal.org/wiki/index.php?title=2000-04-17-Love_One_Another_As_He_Does#Dialogue Abraham] |
[[Category: Physics]] | [[Category: Physics]] | ||
Latest revision as of 23:56, 12 December 2020
Definitions
- 1: the condition of unrestrained motion in a gravitational field; also : such motion
- 2a : the part of a parachute jump before the parachute opens
- b : a rapid and continuing drop or decline <a free fall in stock prices>
Description
In Newtonian physics, free fall is any motion of a body where its weight is the only force acting upon it. In the context of General Relativity where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it and it moves along a geodesic. The present article concerns itself with free fall in the Newtonian domain.
An object in the technical sense of free fall may not necessarily be falling down in the usual sense of the term. An object moving upwards would not normally be considered to be falling but if it is subject to the force of gravity only, it is said to be in free fall. The moon thus is in free fall.
In a uniform gravitational field, in the absence of any other forces, gravitation acts on each part of the body equally and this is akin to weightlessness, a condition which also obtains when the gravitational field is zero such as when far away from any gravitating body. A body in free fall experiences "0-g".
The term "free fall" is often used more loosely than in the strict sense defined above. Thus, falling through an atmosphere without a deployed parachute, or lifting device, is also often referred to as free fall. The aerodynamic drag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching terminal velocity produces the sensation of the body's weight being supported on a cushion of air. [1]
Quote
It is perhaps likened to your journey ahead. You are free-falling without thought of where you shall lay your head to where you shall receive your meals. It is so difficult for mortals to release all that they are, know and have, and in the clutching of this, the energy is spent, and the connection with Father weak. It takes a courageous individual to be willing to be lost to become more. Abraham
