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utkarsh009
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what is pseudo force and centrifugal force? can anyone differentiate between them? is one a special case of the other?
mikelepore said:Centrifugal force is an example of a pseudo-force, that is, an apparent force to someone whose frame of reference isn't at rest or moving with a constant velocity. In the case of centrifugal force, the frame of reference is rotating.
utkarsh009 said:if so then what are the different types of pseudo forces?
This is wrong. Both forces are acting on an object at rest in a rotating frame. The centrifugal force is always there in a rotating frame, regardless if there is a centripetal force to counter it.thebiggerbang said:in brief centrifugal force is nothing but the absence of centripetal force!
A.T. said:This is wrong. Both forces are acting on an object at rest in a rotating frame. The centrifugal force is always there in a rotating frame, regardless if there is a centripetal force to counter it.
That page claims centrifugal force isn't real, but that ignores the real outwards force the tires of a turning car exert onto the surface of the earth. This is more of an argument over termonolgy than actual forces. In the case of the car turning, you have equal and opposing forces at the contact patch of the tires, the tires exert an outwards force onto the surface of the earth, coexistant with the Earth surface exerting an inwards force onto the tires. The inwards force results in inwards acceleration of the car, while the outwards force results in a tiny amount of rotational and lateral acceleration of the Earth (tiny because the Earth is so much more massive).thebiggerbang said:I quoted this "page" ... always acting beacuse that is the pseudo force rising up due to the non-inertial frame! Isn't it?
Yes, in a rotating frame there is always a centrifugal force. But only sometimes a centripetal force to counter it. If there is no centripetal force then there is centrifugal acceleration in the rotating frame (which is just inertial motion in the inertial frame). If there is a centripetal force that counters the centrifugal force, then there is no acceleration in the rotating frame (but there is centripetal acceleration in the inertial frame).thebiggerbang said:I quoted this http://www.regentsprep.org/Regents/physics/phys06/bcentrif/centrif.htm" and I suppose you mean it is always acting beacuse that is the pseudo force rising up due to the non-inertial frame! Isn't it?
is wrong. Centrifugal Force doesn't imply Lack-of-Centripetal Force. For objects at rest in the rotating frame both forces must be there and balance each other. You could say: Centrifugal Acceleration in the rotating frame implies Lack-of-Centripetal Force.Any time the word Centrifugal Force is used, what is really being described is a Lack-of-Centripetal Force.
Only if the object is somehow affected by the rotating frame. The path observed from a rotating frame of an object not affected by the rotating frame doesn't always appear to be affected by a centrifugal force. For example, if an observer (tlme lapse camera) is placed at the north or south pole of the Earth looking straight up, all the stars appear to be orbiting, as if some fictitious centripetal force was causing them to follow a circular path.A.T. said:Yes, in a rotating frame there is always a centrifugal force.
A.T. said:Yes, in a rotating frame there is always a centrifugal force.
Nope, in a rotating frame there is always a centrifugal force. And I have no idea what you mean by "affected by the rotating frame".rcgldr said:Only if the object is somehow affected by the rotating frame.
The coordinate acceleration in the rotating frame is a result of the net force, not just centrifugal force.rcgldr said:The path observed from a rotating frame of an object not affected by the rotating frame doesn't always appear to be affected by a centrifugal force.
And that fictitious centripetal force is called Coriolis force. In this case it is opposed to the centrifugal force, and has twice the magnitude. So half of it cancels the centrifugal force and the other half acts as a centripetal force, keeping the stars on a circular path.rcgldr said:For example, if an observer (tlme lapse camera) is placed at the north or south pole of the Earth looking straight up, all the stars appear to be orbiting, as if some fictitious centripetal force was causing them to follow a circular path.
One where there is a force between an object and a rotating frame. The previous example I used was a ball rolling or sliding inside a cylinder that is rotating on an axis perpendicular to the primary axis of the cylinder. The ball will accelerate outwards due to the tangental force from the walls of the rotating cylinder. I was trying to show an example where there was no real centripetal force acting on an accelerating object.A.T. said:I have no idea what you mean by "affected by the rotating frame".
My mistake. I was thinking of a real "centrifugal" force (reaction to centripetal acceleration) observed from a rotating frame as opposed to the centrifugal force used to correct observation from a rotating frame. What about the case of an observed object on the axis of rotation? What if the object were moving along the axis of rotation?A.T. said:In a rotating frame there is always a centrifugal force.
A reference frame is not a physical object, that can exert forces on masses. There is no such thing as a "force between an object and a reference frame".rcgldr said:One where there is a force between an object and a rotating frame.
The inertial forces depend on the position or velocity, and can be zero in some cases. But there are no such rules like "lack of centriperal force" or "force between object and reference frame" that say when to apply them. In general you always have to assume those inertial forces in rotating frames.rcgldr said:What about the case of an observed object on the axis of rotation? What if the object were moving along the axis of rotation?
rcgldr said:One where there is a force between an object and a rotating frame.
In this case I meant a physical frame that was rotating. Again I was mistakenly thinking about the inertial reaction to a centripetal force from an inertial frame of reference, instead of the fictitious forces from a rotating frame of reference.A.T. said:A reference frame is not a physical object
I guess you mean a physical object that is at rest in the rotating frame.rcgldr said:In this case I meant a physical frame that was rotating.
The are both "real" forces and present in every frame, also the rotating rest frame of the car.rcgldr said:Getting back to the ealier posts and my post #9, in the case of a car turning on a road, I'm not sure how you describe the force exerted by the tires onto the Earth surface, and the force exerted by the Earth surface onto the tires, from the car's perspective as part of a rotating frame of reference.
A pseudo force is a fictitious force that appears to act on an object in a non-inertial reference frame. It is not a real force caused by physical interactions, but rather a mathematical construct used to simplify calculations in non-inertial frames of reference.
A centrifugal force is the outward force experienced by an object moving in a circular path. It is caused by the inertia of the object trying to move in a straight line while constrained to a circular path.
Pseudo force and centrifugal force are fundamentally different in their origins. Pseudo force is a mathematical construct used to simplify calculations in non-inertial reference frames, while centrifugal force is a real force caused by the inertia of an object in circular motion.
Yes, pseudo force and centrifugal force can both be present in a non-inertial reference frame. Pseudo force is always present in such frames, while centrifugal force is only present when an object is in circular motion.
In calculations involving non-inertial reference frames, we must include the effects of both pseudo force and centrifugal force. Pseudo force can be accounted for by using the equations of motion in the non-inertial frame, while centrifugal force can be calculated using the formula F = mv2/r, where m is the mass of the object, v is its velocity, and r is the radius of its circular path.