# 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. ### What minimum speed do we need to give a charged ball?

First, if we sign the speed in the highest point of the ball's trajectory to be ##v_2##, we can write ##m\frac {{v_2}^2 }{l}=T_2+mg-\frac{1}{4\pi \epsilon}\frac{Q^2}{l^2}##. Now, depending on the ball's particular mass, the electrostatic force can be bigger of smaller than its gravity force...
2. ### I Remark on centrifugal force in Heino Falcke's black hole book

Dear all, currently I'm reading the Dutch translation of Heino Falcke's "Light in the Darkness: black holes, the universe and us" as a preparation on a course on black hole I'm giving later this year. In part 1 it contains a remark about space telescopes, and the author imagines us to travel...
3. ### I Velocity of a given planet relative to the Galactic Center

Long time had this question about how fast a planet, dwarf or not or even a rogue asteroid can move relative to the core of the Galaxy, where, if my understanding is correct it has to be a supermassive black hole. Knowing satellites revolves around a planet and this system circles around a star...
4. ### I Work done "against centrifugal force"

Consider a merry-go-round (carousel) with a tube fixed radially on it. I use a pole to push a bowling ball slowly through the tube towards the center. (Slowly, so that the kinetic energy is negligible when the ball reaches the center. Also assume zero friction). What happens to the work that I...
5. ### Fictitious forces on a rigid body

I was confused by how to work this problem in a rotating frame. The solution read that the centrifugal force on the mass should be of magnitude 𝑚𝑤𝑅^2. However, I thought it would be 𝑚𝑤𝐿^2 where L is the distance between the mass and the center of the circle (L = l + R). What am I missing here?
6. ### The interior design of the central trunk of a ring spaceship

For all the attention we‘ve paid to ring habitats, we haven’t talked that much about the interior design of the central trunk yet, around which the rings rotate. Just having one big hollow ship trunk, about 100 metre in diameter, would be a lot of wasted space. It would also be too easy for...
7. ### I Don't Ever Mention "Centrifugal Force" to Physicists

I've just come across the following line while studying (Young & Freedman) and found it amusing. It sounds like a dirty family secret we discuss once and then should never mention again :biggrin:
8. ### Stress in a spinning flywheel

I'm wonder how one could calculate the total mega pascals total mega pascals that can be applied to a spinning flywheel before it exceeds its tensile strength example: a cast iron flywheel is spinning at 10,000rpm(Tangential velocity = 104.72) it has a radius of 100mm and a weight of 500g...
9. ### I How Does Centrifugal Force Affect Objects on a Rotating Disk?

I believe I understand centripetal force, acceleration is necessary for something to spin in a circle because things normally want to continue moving in a straight line (Newton's first law), so a force is necessary to keep something rotating. If you have an object fastened to a rotating disk it...
10. ### B Centrifugal force spinning Basketball

Hi, Looking for Centrifugal force on water droplets on my spinning Basketball at 33 RPM, 45 RPM and 78 RPM
11. ### B Centrifugal Force on Rotating 4" tire / wheel @ 100mph

Heya PhysicsForums! Remote Control Car toy tires and wheels. a 4" tire/wheel rotates at 8400rpm at 100mph. Am wondering how many "g's" the tire "experiences" at that rpm; I imagine it being hundreds of times (if below is accurate am WAY off with my guess) Using a centrifugal force...
12. ### How does Newton's 1st Law impact centrifugal force? Does it exist?

The reading that I have says that centrifugal force (center fleeing) does not exist
13. ### Inconsistent problem about centrifugal/contact force

This is problem 49 in chapter 6 of "Physics - 9th edition". A similar question was asked here several years ago (although with a different height). The figure is below. I added point A and angle \theta . The solution is pretty easy. For the purpose of my discussion I'm assuming that the height...
14. ### Question on hoop stress tension in rotating objects

Hi, I have a question about hoop stress or tangential force acting within a spinning object such as a solid flywheel. As described in a textbook I’ve seen, the hoop stress tension force acting as if across the diameter of the object, trying to pull it apart, is a resultant of forces acting...
15. ### Gravitational force equals centrifugal force?

Book says that correct answer is d) but I can't understand why. If the result of gravitational and centrifugal force is 0N then there is no force that would keep those objects inside the spacecraft orbiting around the planet. Or am I just completely wrong? Thank you for your help.
16. ### Gravity, heat, flooding, and centrifugal force on a tidal-locked planet

Hi. I'm a science fiction author whose first novel Hemispheres, published through RockHill Publishing, explored a tidal-locked planet (Gliese 581g) where a group of activists increased its rotation to bring daylight cycles to both hemispheres. Now I'm writing the sequel, and there's ecological...
17. ### Coriolis Force and Centrifugal Force

Hello! So for a) I have done the following m = 400t = 400000 kg v = 300 km/h = 83,3 m/s ##\alpha## = 50 (degrees) Now this is the formula for the Coriollis effect $$F = 2 \cdot m (v × \omega)$$ So in a book I found in the library regarding physics I've found a similar example that used...

19. ### Rectilinear movement seen from a rotating reference frame

Let's suppose there's some platform that is rotating with angular speed omega and has a radius R. At t=0 we release some object from the border, which has an initial speed perpendicular to the radius direction with magnitude \omega R and we want to know its position at t=T with respect to the...
20. ### Difference between centrifugal force vs reactive centrifugal force?

Difference between centrifugal force vs reactive centrifugal force? and practic example
21. ### Understanding Pseudo-Forces in Non-Inertial Frames

I know that, if my ##X## axis is aligned with the arm, there is friction pointing to ##O## and the ##x## component of the weight. Then, on the ##Y## axis, there is the normal force and the ##y## component of the weight. Supposing that I am situated on the arm (non inertial frame), where is the...
22. ### I Relativistic centrifugal force

I first thought of this problem when I came across the "Ehrenfest Paradox", and realized that as velocity approaches c, the measured force must diverge to infinity as the velocity approaches c.
23. ### I Adhesive force between cutting oil and metal chips?

I am working on a project to remove cutting oil from waste metal chips. I need to know the retationship between viscous force of oil and centrifugal force required to remove oil from chips, so that I can calculate the RPM P.S Design is attached
24. ### Why Centrifugal Force in the Derivation of Curvature Drift

Homework Statement This is a question about a pretty basic plasma physics derivation. In the standard derivation of the Curvature Drift of a charged particle in a magnetic field with curvature, the force that they use is the "imaginary" centrifugal force (or the force the guiding center sees in...
25. ### Question About centrifugal force of a moving car

Homework Statement The Actual Question is that: A car is moving on a circular hill with radius R. what is the maximum speed it can have at the apex of the hill such that it doesn't jump of from the hill. I know the solution but I want to know how will be the equations if the velocity is...
26. ### Centrifugal Force Experienced at the Earth's North Pole

If we standing in the equator, then centrifugal force caused by Earth rotation directly balanced by gravity force. But what if we standing in the high altitude or in the pole? In the pole at the distance like 40 km from north pole (so the north pole inside the horizon plane), the gravity have no...
27. ### Does a rotating conductor generate a voltage change

Does a rotating conductor generate an electrical potential due to charges "feeling" a centrifugal force?
28. ### Relation between centrifugal force and speed

Does centrifugal force generate in increase in overall speed? For example, if I am driving down a highway on-ramp which goes in a circular fashion, with my speed slowly increasing, does my overall speed increase because of the centrifugal force generated from the circular on-ramp? Is more force...
29. ### B Centrifugal Force in Angular SHM: Explained

Does centrifugal force (mv^2/r) act in any position of angular SHM? Please explain.
30. ### Explanation: motorcycle leaning without centrifugal force?

Hi the question is about bicycle and motorcycle dynamics How can we explain the motorcycle leaning in turn without using the centrifugal force term? You know the correct term for rotational motion is the centripetal force and it is toward the centre. I have a problem with rotational equilibrium...
31. ### Rotary or centrifugal jet spinning (nanofiber)

Hi, I am a research student, working on rotary jet spinning. while spinning, nanofibers are formed but it's not attached properly to the collector. It became like a spider web. You guys have any idea why it became like that?
32. ### Does Centrifugal Force Cause Curvature Drift in Plasmas?

Curvature drift in plasmas arise due to the centrifugal force that a particle sees when considering its guiding centre. Thus if one is following from the frame of the guiding centre, this drift will be observed. But for a stationary observer (let's say an experimentalist watching the plasma in a...
33. A

### B What is the Net Force on a Banked Curve?

I understand why when deriving the formulas for cars on banked curves, the net force in the Y direction is zero. However, when I google how to derive them, people say that there is a net force greater than zero in the X direction. This is not what my professor says in his explanations however...
34. ### Friction guiding a car around a curve

friction is causes the circular motion in the car around a curve, and if we draw free body diagram we will see the friction force must be opposite the car motion so the force of friction not toward to the center of the curve ,so the force of friction must be not the centripetal force ,mustn't it?

I've been thinking about centripetal force and its effects on motion in uniform circular motion. I've actually found it difficult to accept that velocity magnitude can ever be maintained constant. Here is why: if this is our velocity vector, v, at the top of the circle: → Then the centripetal...
36. ### Normal force in a curvilnear motion

Homework Statement The system shown is initially at rest when the bent bar starts to rotate about the vertical axis AB with constant angular acceleration a 0 = 3 rad/ s2 . The coefficient of static friction between the collar of mass m = 2 kg and the bent bar is f.Ls = 0.35, and the collar is...
37. ### Magnitude of force of a disk on a circular track

Homework Statement A small disc, radius r and mass m = 7.9 g, rolls on its edge. The friction with the track is enough to prevent slipping. When released, it rolls down the track (sketch) and reaches a circular section with radius R = 5.1 cm, which is very much greater than r. The initial...
38. ### Random question regarding centrifugal force.

Hello, I am somewhat new to this forum but have a basic question that I have had for a long time. please excuse it if it is a dumb question. I understand how centrifugal force works - you spin something around and it wants to fly away from the center. And I understand that there are...
39. ### Centrifugal force on water in a glass

Homework Statement There is a cyllindrical glass (r=0.05 m) full of water. It is rotating around its vertical geometric axis with 3 turns per second. How many centimetres higher is water at the rim than in the centre of the glass . Water rotates together with the glass. Homework Equations...
40. ### I Consider Coriolis force or not?

Hello, my question is very short. I have a spinning bar, with a small ring threaded. I know that for analyzing the problem I have to consider the centrifugal force that makes the small ring go away from the center. My question is do I have to also consider the coriolis force? : - 2m (w x v'), or...
41. ### Is centripetal force greater than centrifugal force?

Why is resultant force directed towards the center of the circular path? Is it because centripetal force is greater than centrifugal force? If the centrifugal force is greater, then the ball will rise? (If the string doesn't snap)
42. ### Centrifugal pump restricted output

I am also constructing a small boat as a test bed for a much larger houseboat. If we forget about practicality issues... and accepting that my BS econ degree from the 60's isn't helping me much, I have a simple question with a difficult answer I guess. 2 stage centrifugal pump. (Standard...
43. ### Centrifugal force problem

I want to understand the problem of centrifugal force with an aircraft in a turn. If I keep the wings level and input a certain amount of left rudder the aircraft skids and throws the turn coordinator ball to the right due to centrifugal force. The solution is to bank the wings until the ball...
44. ### Would space stations of sci-fi fame actually work?

Would a spinning space station as depicted below that use centrifugal force to create artificial gravity actually work? I'm thinking that it would not, this is because the centrifugal force would not affect an astronaut inside unless he was actually fastened mechanically to the hub. The fact...
45. ### Angular momentum is conserved, but KE is not. How to find out why?

This (photo) is a very typical example of conservation of angular momentum, but my trouble arrises from trying to prove that the difference of energy will have to correspond to work, by calculating the work done by you to alter the moment of inertia. I have spent a lot of time in this, but I...
46. ### Having problem with centripetal and centrifugal force

Hi,I was reading about the centripetal and centrifugal forces then I felt a bit of contradiction in the explanations. It is said that the centripetal and centrifugal forces are the action-reaction pair of Newton's 3rd law and so they never act upon the same body.Centripetal force is acted upon...
47. ### Centripetal force and spinning discs

Apologies for a possibly very basic question. I was recently asked by someone to explain to them the answer to the following classical mechanics (uniform circular motion) problem: Consider two discs of different radii, attached to one another such that they are concentric, and each containing a...
48. ### I The "real" reason why some galaxies are flat

I'm doing research on why some galaxies and other phenomenon like Saturn's rings are flat. There seems to be two answers. Here they are in shortened form: 1) When the galaxy is forming, there is some net angular momentum in some direction.Over time, all particles with an angular momentum...
49. ### Centrifugal force on Earth and deviation of free falling obj

Centrifugal force due to rotation of the Earth has among its effects the deviation towards the equator of a ball falling from height ##h## vertically on Earth. I do not understand what is the inertial explanation of this phenomenon. Once the ball is released there is no centripetal force that...
50. ### Connetion between centrifugal force and weight force

Can someone explain me what is the connetion between centrifugal force and weight force thanks ? In which situation should I use the centrifugal force (that is a fake force) ?