What is Centrifugal force: Definition and 203 Discussions

In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis which is parallel to the axis of rotation and passing through the coordinate system's origin. If the axis of rotation passes through the coordinate system's origin, the centrifugal force is directed radially outwards from that axis. The magnitude of centrifugal force F on an object of mass m at the distance r from the origin of a frame of reference rotating with angular velocity ω is:

The concept of centrifugal force can be applied in rotating devices, such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planetary orbits and banked curves, when they are analyzed in a rotating coordinate system.
Confusingly, the term has sometimes also been used for the reactive centrifugal force, a real inertial-frame-independent Newtonian force that exists as a reaction to a centripetal force.

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  1. A

    Centrifugal force and artificial gravity

    In lecture 5 of MIT's OCW 8.01 , Prof. Lewin says that when you're in in uniform circular motion, the perceived gravity is always in the opposite direction as the push or pull (so if you're holding onto the end of a rope that's being spun around horziontally, the rope is pulling on you and you...
  2. B

    What Causes the Counterbalancing Force in a Frictionless, Rotating System?

    Hello, the problem I am working on is: "A puck of mass m = 51.0 g is attached to a taut cord passing through a small hole in a frictionless, horizontal surface (see figure below). The puck is initially orbiting with speed v_i = 1.30 m/s in a circle of radius r_i = 0.310 m. The cord is then...
  3. C

    Understanding the centrifugal force

    I'm learning about mechanics in noninertial frames and I'd like to clarify the apparent centrifugal force. To set things straight, Centrifugal force = Fcf = m(Ω×r)×Ω where Ω×r is the instaneous velocity at a point on the outside of a circle (or other rotating path) and Ω is the...
  4. P

    Is Centrifugal Force Real or Fictitious?

    In physics today, my teacher told me that Centrifugal force is a fake force? Is this true? What exactly is Centrifugal force? Any help would be greatly appreciated!
  5. B

    Centripetal Force vs Centrifugal Force

    Hi, thank you for reading this topic. This is something that really bothers me...First of all let me say that I know what the terms centripetal and centrifugal stand for. What's the problem then? The problem is that I've always read that the centripetal force is an actual force and that...
  6. K

    What kind of curve would you feel more centrifugal force?

    Would you feel more centrifugal force going around a small radius curve or a large radius curve going at constant speed? Why?
  7. L

    How Does Centrifugal Force Compare to Gravity in Car Cornering Dynamics?

    Homework Statement The friction coefficient between the tires and the road is 0.6. What is the maximum velocity of the car without it sliding out of the turn. The radius of the curve is 80m. The curve is considered to be horizontal (as ridiculous as it may sound)Homework Equations F = ma The...
  8. S

    Help with physics homework regarding friction, tension, springs and centrifugal force

    Homework Statement The first problem I am having trouble with is as follows: A child pushes a 40kg sled across the ice at a constant speed. If μk = 0.05 calculate the force applied to the sled. Homework Equations I know that f=\muFN The Attempt at a Solution I know that the...
  9. G

    How Does Angular Velocity Affect the Angle of a Spring-Mass System?

    hi i found the following equation that a spring(with constant k) , a mass m rotating with angular velocity ω, will have a constant angle \alpha to the vertical axis that is given by cos(\alpha)=\frac{g}{\omega^2 l}(1-\frac{m \omega^2}{k}) this looks similar to something like...
  10. S

    G-Force and (possibly) Centrifugal force applied to the rotation of a car

    1. I'm in my first year of physics, and the end-of-year project is a bit of a doozy: find two examples of misapplied physics in movies and explain how it's wrong. For my first example, I chose a scene from the movie "The Iron Giant," in which the Giant picks up a car with Hogarth, our child...
  11. A

    What happens when a steel wheel explodes due to centrifugal force?

    What are the consequences of the explosion of a steel wheel by the action of centrifugal force and spinning at high speed? Am I creating the energy of this explosion?
  12. G

    Why Don't Rockets Use Centrifugal Force for Launch?

    hi i was wondering why rockets always start upright, as if they would start in a position parallel to the surface of the earth(or at least almost parallel to the earth, but at the equator this should not be such a problem, if there are no mountains or anything else close to the point where...
  13. azizlwl

    Centrifugal Force and the Path of a Moving Particle in a Rotating Tube

    "Centrifugal force" Homework Statement A smooth horizontal tube of length l rotates about a vertical axis. A particle placed at the extreme end of the tube is projected towards O(axis) with a velocity lω while at the same time the tube rotates about the axis with constant angular speed ω...
  14. L

    Centrifugal Force Explained: Inertial vs Rotating Frames

    I don't understand how its a fictitious force and why you need to be in the rotating frame of reference to observe it? In the example of the moon and the Earth and its tides. You have the centripetal force causing the tides to increase at the point where the Earth is facing the moon and the...
  15. N

    Centrifugal Force Homework: Relationship to Radius?

    Homework Statement Hi, I am confused about the relationship between the centrifugal force and radius. The centrifugal force equation for an object having constant mass and angular velocity moving around the Earth on GRS80 reference is Fc = m w^2/r (m=mass, w^2=angular velocity of the...
  16. K

    Centripetal and Centrifugal force

    I just read that Centrifugal Force is a false force. It does not exist. Inertia (which is not a force) is mistakenly called Centrifugal force. Now, here is my question According to Newton's 3rd law of motion, forces always exist in pairs; action and reaction. Centripetal force which is the...
  17. G

    Influence of Centrifugal force in 'g'

    Influence of "Centrifugal" force in 'g' Hello everyone, I was wondering one of these days if the 'centrifugal' force due to the rotation of the Earth in the Equator could cause any difference in the value of the gravitational acceleration; namely it would be supposedly less than the real...
  18. G

    Analogy between centrifugal force and gravity

    I understand the equivalence of gravity and uniform linear acceleration. But I'm less clear on the example involving circular motion (merry-go-round) and the equivalence of gravity and centrifugal force, because I'm unclear about the connections between SR & GR. The example does illuminate...
  19. N

    [ Spring pendulum ] Centrifugal Force transmissibility

    Hey folks, I just wonder how you guys think about this. Assume that there is a spring pendulum rotating at hinge (Free swing or forced swing). In this case, can I calculate force transmissibility (transmitted force amplitude to ground via spring devided by centrifugal force amplitude) ...
  20. C

    Centrifugal force, fictitious?

    If you've ever taken a bicycle wheel off, held it with both hands on either side of the axle and try to lean it side to side whilst the wheel is spinning it is very difficult, the wheel fights you and it's almost like the wheel wants to 'tip' about 90 degrees before or after (I can't...
  21. J

    Centripetal and centrifugal force

    In circular motion why the centripetal and centrifugal not get cancelling. .?
  22. Andrew Mason

    Is the concept of reactive centrifugal force valid?

    I came across this http://en.wikipedia.org/wiki/Reactive_centrifugal_force" I think this is Wikipedia nonsense. There is only one centrifugal "force" and it is the inertial effect or "pseudo force" or "fictitious force" observed in a non-inertial frame of reference. The authors of these...
  23. R

    Centrifugal force and direction

    we wouldn't experience the centrifugal force unless we change direction. Suppose we are flying an twin engine airplane and one side engine fails, to counteract this the pilot applies opposite rudder and flies straight. Would we experience the centrifugal force and does the turn indicator...
  24. M

    How do electrons maintain a stable distance from the nucleus?

    Please correct me if I am wrong in any of this 1) Electrons are able to go around the nucleus of an atom due to the centrifugal force resulting from the weak/strong force (one of them) 2) Quantum physics says that particles can be in 2 places at the same time. 3) Therefore can't an electron...
  25. D

    Calculating Centrifugal Force: 10lbs Steel Wheel, 6in CG, 7200rpm

    Homework Statement 10 lbs. steel wheel with its center of gravity at 6 inches from the axle rotating within a circular frame at 7200 rpm Homework Equations 10lbs. x 6 inches x 72002rpms x 0.000028416(constant) = 88,385 lbs. The Attempt at a Solution 10 x 6 x 72002 x 0.000028416...
  26. P

    Rotary Swivel Assembly: Effects of Torque and Centrifugal Force

    Hello, I'm designing for a rotating swivel assembly that will be used for a high pressure cutting system. The rotary swivel is set for an allowable 2800 bar of pressure but has to rotate at 300 RPM while allowing a pressure of 12-15,000 psi pass through it. My question consists of two...
  27. H

    Rotor Tip Weight (Centrifugal Force)

    What formula would one use to determine the centrifugal force at the tip of a rotor of 35ft diameter, rotating at 392rpm? Would any other factors be necessary, such as blade thickness, weight, etc? A pilot I work with doesn't believe the weight at the rotor tip would be measured in tons. I...
  28. A

    Simple centrifugal force problem

    simple centrifugal force problem please help i have a 2m long tube spinning around its center at w=1 theres a 1 kg projectile at 1 m distance from the axe inside the tube that is released at a certain moment what speed does the projectile have when it leaves the tube? please show me...
  29. H

    Pumping fluid against a centrifugal force

    Hello. I am in need of some assistance regarding a theoratical problem I have. It goes something like this: Imagine a vertically placed axle, rotating at a constant angular velocity (omega). From the middle of this axle extends an arm and on the edge of that arm is a unit containing...
  30. K

    Centrifugal Force- Finding Speed of Satellite

    Homework Statement In order for a satellite to move in a stable circular orbit of radius 6736 km at a constant speed, its centripetal acceleration must be inversely proportional to the square of the radius r of the orbit. What is the speed of the satellite? The universal gravitational constant...
  31. T

    Direction of Centrifugal Force?

    I am trying to understand how centrifugal force works when applied to a train. For example, if I had a train that had zero super elevation, was traveling along a curve, of some radius at some speed then the centrifugal force acting on the train would be of a certain magnitude which would act...
  32. T

    Does centrifugal force have a gradient

    Hello I was wondering if centrifugal force had a gradient, what i mean by this is this:- A train is traveling on a straight section of track with no centrifugal force. The train then travels along a transition, as the train travels along the transition, the centrifugal force builds up...
  33. Telemachus

    Centrifugal Force Homework: Airplane 150m Radius, 80kg Pilot

    Homework Statement I have this exercise which says: An airplane moves along a circular path of 150 meters radius, contained in a vertical plane with constant speed module 200km / h. a)Determine the force resulting from the interaction between the seat and the pilot, whose mass is 80kg, at...
  34. H

    Bifurcated Asteroid - Centrifugal force

    Hi, my math and physics are poor so please bear with me. I have an bifurcated asteroid - 2 components. A sphere diameter 1.5km (m1) and a larger sphere, 2km in diameter (m2). The spheres are touching. System spins around the long axis. Assuming both bodies have internal strength (not...
  35. L

    Centrifugal force versus gravity (ball on a joint placed on rotating shaft)

    Homework Statement Basically, this is the problem. [PLAIN]http://img180.imageshack.us/img180/3598/physicsproblem.png It's related to some design research I'm doing regarding a centrifugal control valve. This is a type of valve that controls the fluid flow based on the centrifugal...
  36. S

    Why do astronauts feel weightless inside a space ship and centrifugal force?

    Hello everyone, Ok so I read that the reason they are in free fall is because they are going in a circle like this , and the Earth curves away from them at the same time or something, could anyone explain it to me simply. Also why don't astraunauts get pushed to the periphery of the...
  37. M

    Rotating reference system - centrifugal force

    Hi! Can someone explain this expression for the centrifugal force? F = -mw x w x r, where the underline refers to vectors. (sorry for notation) w is the angular veolcity, m mass, a r is the radial vector. I can't really see where the expression comes from. Can you indentify and...
  38. U

    Difference between pseudo force and centrifugal force

    what is pseudo force and centrifugal force? can anyone differentiate between them? is one a special case of the other?
  39. C

    What are the units for centrifugal force and how do you calculate it?

    I found this on Wikipedia for the equation relating to centrifugal force. F = d/dt (m*v) So I have my mass and velocity but I just multiplied the two, that can't be correct can it. You have to derive something I imagine. Also would the units just be in lbs or Newtons. I'm using feet/s...
  40. K

    What Causes Imbalance in Rotating Bodies?

    Hi, I've read about the balancing of rotating masses. In the context every author(even J.E.Shigley in his book Theory of machines & mechanisms) mentions that a rigid body while rotating, it experiences a "Centrifugal Force" . Now we know that centrifugal force is a pseudo force when we analyze...
  41. G

    A question about centrifugal force

    Say the force is 1g for an object rotating around an axis. If the object is a platform that is facing the center how would forces act on an item placed at different areas on the platform? Thanks.
  42. G

    Helium balloon centrifugal force

    Helium balloon "centrifugal" force Homework Statement Assume that you are driving down a straight road at a constant speed. A helium-filled balloon is tied to a string that is pinned to the front seat. Which way will the balloon swing when you apply the brakes? Explain why. Homework...
  43. S

    Relation of gravity with centrifugal force & gyroscopic effect?

    Is there any relation of gravity with centrifugal force & gyroscopic effect? Rotating body shows centrifugal force due to radial acceleration α=rω2. This causes force just like gravitation force. Rotating gyroscope doesn’t fall & maintain motion. This is just like anti-Gravity. Can I say that...
  44. R

    Setting up a centrifugal force question

    Suppose we have a merry-go-round of radius 10 meters. There's a thin glass tube with cross-sectional density d going radially from the center of the merry-go-round to the edge. In the glass tube one meter away from the center, there's a marble of mass m. The merry-go-round completes one...
  45. F

    Use of centrifugal force in outer-space

    Reading the Arthur C. Clarke novel: "Rendezvous with Rama"; something keeps nagging me about the descriptions of their experience inside the ship they encounter, which is a huge, rotating, hollow cylinder. It's rotation makes a sort of "pseudo-gravity" by way of centrifugal force. The issue I'm...
  46. J

    How Do We Calculate Centrifugal Acceleration in Celestial Bodies?

    Calculate the centrifugal acceleration associated with a.) The rotation of the Earth around its axis, as measured on the equator b.) The Earth moving around the Earth-Sun centre of mass. Assume the orbit is circular c._ The Sun moving around the Earth-Sun centre of mass. Same assumption as...
  47. S

    How do you separate things from centrifugal force?

    How do these machines work? I mean there is no such thing called centrifugal force in real yeah. It is basically inertia. So can anyone tell me how it can be used to separate molecules and how different masses move differently. I haven't see the machine yet so if you can explain that would be...
  48. B

    How does the centrifugal force affect your weight on a scale?

    Um, I suppose this is very basic but I just got kind of confused. Okay suppose you are standing and swinging a rope with a mass attached to its end, so that the circular trajectory of the mass at the end of the rope lies in a vertical plane. And suppose you are stood on a weighing scale. Does...
  49. A

    Fluid under centrifugal force (Basic)

    Hi, What happens to the fluid in a cylinder that is spinned around it's central axis? Would it matter if there would be a bit of air? Thanks very much, Alex
  50. A

    About 'origin' of the centrifugal force

    Just want to make sure my concepts about this fictitious force is correct... " Assuming Joe is spinning around on a stationary point, while holding a string tightened onto stone. Therefore, he is providing a centripetal force to the stone through the string, so that it rotates around him...
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