Editing Talk:1318: Actually

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Fixed factual error about sum of angles of a triangle in a closed geometry. An example of closed geometry is spherical geometry, where sum of angles of a triangle is π < A + B + C<3π http://en.wikipedia.org/wiki/Spherical_trigonometry . Previous text wrongly stated that A+B+C would be smaller than π in closed geometry and greater in open geometry. [[User:MGitsfullofsheep|MGitsfullofsheep]] ([[User talk:MGitsfullofsheep|talk]]) 08:50, 17 January 2014 (UTC)
 
Fixed factual error about sum of angles of a triangle in a closed geometry. An example of closed geometry is spherical geometry, where sum of angles of a triangle is π < A + B + C<3π http://en.wikipedia.org/wiki/Spherical_trigonometry . Previous text wrongly stated that A+B+C would be smaller than π in closed geometry and greater in open geometry. [[User:MGitsfullofsheep|MGitsfullofsheep]] ([[User talk:MGitsfullofsheep|talk]]) 08:50, 17 January 2014 (UTC)
  
About the oblate configuration: why attribute it to centripetal force? Because centrifugal force is an "apparent" force? Well centripetal force from gravitational pull is actually balancing the centrifugal force caused by rotation of the earth. The whole "centrifugal force does not exist" thing is a misconception. It's an inertial force and writing the equilibrium equations for an object in the rotating reference frame (the one we experience everyday) at latitude phi you see: gravitational pull toward the center of the planet + centrifugal force away from the axis of rotation= mass*g(phi). This g(phi) is not the same in every spot of the earth, it changes in value and direction (does not always point exactly to the center of the earth) with latitude.{{unsigned ip|108.162.229.65}}
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About the oblate configuration: why attribute it to centripetal force? Because centrifugal force is an "apparent" force? Well centripetal force from gravitational pull is actually balancing the centrifugal force caused by rotation of the earth. The whole "centrifugal force does not exist" thing is a misconception. It's an inertial force and writing the equilibrium equations for an object in the rotating reference frame (the one we experience everyday) at latitude phi you see: gravitational pull toward the center of the planet + centrifugal force away from the axis of rotation= mass*g(phi). This g(phi) is not the same in every spot of the earth, it changes in value and direction (does not always point exactly to the center of the earth) with latitude.
: I second this. The centripetal force would actually be the gravity of earth. Attributing the oblate shape of earth to this is just plain wrong, since it pulls inwards, not outwards. Actually all forces could be called "apparent" forces, since they're really just constructs to help you calculate the acceleration of a body. There's always a (local) reference frame where a particular force doesn't "exist". {{unsigned ip|173.245.53.131}}
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: I second this. The centripetal force would actually be the gravity of earth. Attributing the oblate shape of earth to this is just plain wrong, since it pulls inwards, not outwards. Actually all forces could be called "apparent" forces, since they're really just constructs to help you calculate the acceleration of a body. There's always a (local) reference frame where a particular force doesn't "exist".
 
:: Sure, there is always such frame, but gravitation is real force anyway because we can measure the higgs field by detecting higgs bosons. At least I think we can. Failing that, electromagnetic forces are real because we can measure electromagnetic field by detecting photons, this I'm sure of :-). -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:23, 17 January 2014 (UTC)
 
:: Sure, there is always such frame, but gravitation is real force anyway because we can measure the higgs field by detecting higgs bosons. At least I think we can. Failing that, electromagnetic forces are real because we can measure electromagnetic field by detecting photons, this I'm sure of :-). -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:23, 17 January 2014 (UTC)
 
:::Come now. Do you really expect me to do coordinate substitution in my head while strapped to a centrifuge? [[User:Diszy|Diszy]] ([[User talk:Diszy|talk]]) 15:44, 17 January 2014 (UTC)
 
:::Come now. Do you really expect me to do coordinate substitution in my head while strapped to a centrifuge? [[User:Diszy|Diszy]] ([[User talk:Diszy|talk]]) 15:44, 17 January 2014 (UTC)

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