Centrifugal force

Centrifugal force . it is a fictitious force that appears when describing the movement of a body in a rotating frame of reference. The term “centrifuge” means that it “flees from the center”. Indeed, an observer located on the platform of a flying chair that rotates with angular velocity ω (non-inertial observer) feels that there is a forceacting on it, which prevents it from resting on the platform unless it itself performs another force directed towards the axis of rotation, a force it must have as a module, the distance at which it is from the axis of rotation. Thus, apparently, centrifugal force tends to move objects away from the axis of rotation. In general, the centrifugal force associated with a mass particle that in a rotating reference system with an angular velocity and at a distance from the axis of rotation is given by: F cf = – mw x (wxr)


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  • 1 Applications
  • 2 Centripetal force versus centrifugal force
  • 3 Confusion about the term
  • 4 See also
  • 5 Source


Hydrocyclones: The simplest way to use centrifugal force for separation is hydrocyclones . It is not actually a centrifuge: since the centrifugal separation is produced by the movement of the mud, induced by the injection of the feed material in a tangential way. The principle of operation is based on the concept of terminal velocity of sedimentation of a solid particle in a centrifugal field.

Centripetal force versus centrifugal force

Centripetal force is any force or component of force directed toward the center of curvature of a particle’s path. Thus, in the case of uniform circular motion , the centripetal forceIt is directed toward the center of the circular path and is necessary to produce the change in direction of the particle’s velocity. If no force were to act on the particle, it would move in a straight line with constant speed. Centrifugal force is not a force in the usual sense of the word, but is a fictitious force that appears in non-inertial reference systems. That is, the apparent force that a non-inertial observer seems to perceive as a result of the non-inertiality of his frame of reference. Thus, for example, if a body is rotating around a fixed force center, the only real force acting on the body is the force of attraction towards the center of the trajectory (centripetal force) necessary, from the point of view of a stationary observer (inertial, [X, Y, Z]) so that the body can describe a curvilinear trajectory. Said real force, Fcp, (the tension of the rope in the example illustrated in the Figure) provides the centripetal acceleration characteristic of all curvilinear movement. However, an observer located in a frame in which the body is at rest (frame in rotation [x, y, z] and, therefore, not inertial) will observe that the body does not show any acceleration in the direction of the force. Fcp applied (which can be measured by inserting a dynamometer in the string in the Figure). To reconcile this result with the requirement that the net force acting on the body be null, the observer imagines the existence of a force equal to and opposite to the centripetal force; that is, it postulates the existence of a centrifugal force, Fcf which has no real existence and which is only useful to the non-inertial observer in order to write Newton’s second law in the usual way. Let’s take another example to clarify the concept. Imagine a passenger in a car taking a sharp left turn with a certainspeed . The inertia associated with the passenger’s mass opposes any change in the direction of movement of the passenger, impelling him to continue his initial rectilinear trajectory. Since the car turns to the left, the passenger feels displaced towards the door on his right. Once the passenger makes contact with the door, it will exert the necessary centripetal force on the passenger so that, like the car, it can turn to the left. The friction between the seat and the passenger’s pants also helps to counteract the centrifugal effect and, if the turn occurs at low speed, it may be enough to prevent the passenger from sliding on the seat and provide the necessary centripetal force for the turn .

Confusion about the term

The fictitious or false character of the centrifugal force can give rise to some confusion in its interpretation, especially when it is confused with the reaction of the centripetal force, by virtue of Newton’s third law or Principle of action-reaction, forgetting that this reaction does not act on the body but is exerted by the body. Currently, the centrifugal force tends to be played down when teaching circular motion ; instead the importance of centripetal force is enhanced, since it is the real force and responsible for maintaining circular motion and providing centripetal acceleration. However, when it is inevitable to describe movement in a frame of referenceIn rotation, such as when describing the motion of a long-range projectile relative to the Earth’s surface, it will be inevitable to refer to the centrifugal force and other dummy forces, such as the Coriolis force

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