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hello94857
Feb 8, 2014, 06:03 AM
I understand centrifugal force is a force that moves an object away from the axis and thus the faster it goes (rotates) the more force is generated and the close to the axis it gets the faster it will rotate with no added outside source providing acceleration. I understand centripetal force is a force that is provided by a third source of energy providing the containment and thus pushing back against centrifugal force. My questions are, for example an object in orbit around the sun, obviously there are centrifugal and centripetal force at play on it are the centrifugal and centripetal forces provided by a third closest(largest) source of gravity? And if there where a hypothetical existence where the only sources of gravity where flat and equally given and something rotated on the surface of it would there still be a centrifugal and centripetal force reaction or is the reaction also accounted to a third source of gravity that has curvature ?

ebaines
Feb 8, 2014, 08:23 AM
There really is no such thing as "centrifugal force" - it's a fictitous force that is a consequence of the inertia of a body in a rotating reference frame. It's centripetal force that causes the object to move on a curved path. This force, applied by some central mechanism, causes the object to accelerate towards the center of rotation. Remember that \vec F=m \vec a, so the force being applied in the direction of the center of rotation causes the object to accelerate inward. In the case of an object in orbit, that force is the force of gravity between the satellite and the body the satellite is in orbit about. For the Earth orbiting the sun the central force is the pull of the sun's gravity on the Earth. If there were no central source of gravity (i.e. no sun) then the Earth would move off in a straight line. An object can not move in a curved path unless some force is acting on it, so I don't understand what your last question is getting at - please clarify.

hello94857
Feb 9, 2014, 04:05 PM
yes helpful thanks

hello94857
Feb 9, 2014, 04:10 PM
Hmmmm, I think I may have it from what you say, the faster you go in rotation the more you would weigh (g force) until eventually you become to heavy to maintain the rotation and break the grip with the force holding you in rotation and thus go off your curvature into a straight line.

hello94857
Feb 9, 2014, 05:41 PM
To clarify, centrifugal force is not a force but an effect when something is forced to change its forward momentum. Moving objects can only ever move forward, when something rotates it is still trying to move in a straight line but a force is forcing it to take a curved path. Momentum is weight in motion.

ebaines
Feb 10, 2014, 05:25 AM
You were doing OK up to this point:


Momentum is weight in motion.

Momentum is mass in motion.

Weight is the force of gravity acting upon a mass.

hello94857
Feb 10, 2014, 05:58 PM
Yes, I need to think more specifically, thank you.