Does Centrifugal Force Act During or After Spinning in a Centrifuge?

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Discussion Overview

The discussion revolves around the nature of centrifugal force in the context of a centrifuge, specifically whether it acts during the spinning process or only after it has stopped. Participants explore the implications of centrifugal force and centripetal force from different perspectives, including the experiences of the test tubes and observers.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that centrifugal force acts while the centrifuge is running, not after it has stopped.
  • One participant expresses confusion about the nature of centrifugal force, questioning why it acts opposite to centripetal force and how it relates to inertia.
  • A participant provides an analogy involving a box in a car to illustrate the concept of inertia and the effects of centripetal force.
  • Another participant notes that from the test tube's perspective, centrifugal force is perceived, while an observer would see centripetal force acting inward.
  • A later reply challenges the idea that the test tube only observes centrifugal force, emphasizing that the force acting on it is centripetal.

Areas of Agreement / Disagreement

Participants express differing views on the nature and timing of centrifugal force, with no consensus reached on whether it acts during or after the spinning process.

Contextual Notes

Participants highlight the importance of perspective in understanding the forces at play, indicating that definitions and interpretations may vary based on the frame of reference.

sameeralord
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Hello everyone,

If some test tubes are placed in a centrifuge to separate the liquid in them, does the separation occur after the spinning is finished. I can't see how the centrifugal force can act when the tubes are spinning, does it act after it finishes. Thanks
 
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russ_watters said:
It acts while the centrifuge is running, not after. http://en.wikipedia.org/wiki/Centripetal_force

Thanks for the reply Russ!

Ok then I haven't understood this concept.

centrifugal.free.gif


Ok a person was initially traveling at V direction and then centriptal force acted upon him to make him go in a circle. Now if centrifugal force is inertia, why is acting opposite to centripetal force, shouldn't it act tangent to the circle, if I stop the centripetal force the man would travel tangent to the circle. If inertia is in that direction why is centifugal force acting some other way, also I read that this force really doesn't exist, then how does it separate the liquid. Thanks!

Edit: Ok I think I worked it out. If there is a box in the back seat of the car, and the car is traveling straight and suddenly acted upon by the centripetal force, the box would obviously try to keep moving forward with cars orginal speed, but the centripetal force has already turned the car, so the box is not going to hit the front seat but the side of the car.
 
Last edited:
From the test tube's perspective, there is no centripetal force, but there is centrifugal force. Its the opposite for an observer watching the test tube. Careful not to mix these cases up.
 
Academic said:
From the test tube's perspective, there is no centripetal force, but there is centrifugal force. Its the opposite for an observer watching the test tube. Careful not to mix these cases up.

How does the test tube only observe centrifugal force? The force on the test tube is the centripetal force acting inward.
 

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