# Questions tagged [centrifugal-force]

Centrifugal force is an inertial (pseudo or fictious) force used in a non-inertial frame of reference in order to apply the Newton's laws of motion. If your question is about centripetal force, which is a real force that points towards the center of a circular trajectory, use the tag "centripetal-force" instead.

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### I have designed a 3D gyro but what can I expect after I produce it? [closed]

I have designed a mechanically engineered gyroscope that rotates around 3 planes or 3 axis but I'd like to know what I am expected to see when I've built it. I've already 3d printed a 2 dimensional ...
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### Substituting the conservation of angular momentum into the Binet formula results in contradiction [duplicate]

Background Information The lagrangian of a particle in a central force field $V(r)$ is $$L=\frac12m(\dot r^2+r^2\dot\theta^2+r^2\sin^2\theta\dot\varphi^2)-V(r).$$ The particle must move in a plane, ...
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### Does gravity cause the Earth's equatorial bulge?

The way I understand centrifugal force, I don't see how Earth's daily rotation alone would cause equatorial bulges to form. The usual explanation is that the centrifugal force increases with distance ...
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### If one "fell" from the center of a spinning space station, which was creating "gravity" by using centripetal force, what forces would one feel?

Let's imagine a grand hamster wheel in space. The wheel is very large and is constructed of the same reasonably inelastic material. It has three main features: The first is a solid disk rotating at ...
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### What force accounts for Earth's equatorial bulge in an inertial frame of reference?

I am confused as to how Earth's centrifugal effects from its daily spin can be explained from an inertial frame of reference relative to the distant stars. The usual explanation is that the ...
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### Can you fall in a Gravitron centrifuge ride?

I went on a Gravitron ride with my 5 year old son. He became "hysterical" with fear and started pushing himself off the wall. I my arm across his body trying to keep/push him back as he was ...
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### Why aren't fusion reactors using centrifuges?

If fusing of nuclei in stars requires pressure, heat, and gravity, why not use a centrifuge to increase the gravity? We currently have the technology to make diamonds, and generate immense ...
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### Gravitational Potential of a Slowly Spinning Planet

I'm working on a problem in Thorne & Blandford's Modern Classical Physics regarding the shape of a constant density, spinning planet (Exercise 13.5). It asks you to argue that the gravitational ...
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### Alternative formula for centrifugal force

The centrifugal force has the formula $$f_C=\Omega^2r$$ and vectored $$\vec{f_C}=\vec{\Omega} \times(\vec{\Omega}\times \vec{r})$$ However there is also the known formula $$f_C=\frac{v^2}{r}$$ ...
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Background: Let’s say we have a trajectory $\vec{y}(t)$ expressed in coordinates of an accelerated reference frame. In an inertial reference frame the trajectory is given by: $\vec{x}(t)=R(t)\vec{y}(t)... • 235 0 votes 3 answers 118 views ### Why is it said that gravity is weaker at the equator due to centrifugal force? [duplicate] Gravity would only be weaker at the equator if mass is not the only thing that produces gravity or if there is dense enough matter near, or at, the center to offset the additional volume of mass that ... 0 votes 3 answers 108 views ### Apparent weight due to the rotation of earth My concern here is that, if you were to calculate the apparent weight of an object due to earth's rotation at the equator, most text books use centripetal force and it works totally fine, but when it ... 0 votes 1 answer 54 views ### Could centrifugal force save this scene in movie "Gravity"? The scene on movie "Gravity" where George Clooney dies has taken a lot of heat, and I could not find one single person able to defend it, as physics is concerned. There is even an interview ... • 909 1 vote 0 answers 26 views ### In a centrifugal separator how does the heavy or light phase move upwards? I've been studying about the working principles of a centrifugal separator. Even though i understand how centrifugal force separates the liquid into 2 phases(heavy and light) i cant make sense of how ... 0 votes 1 answer 14 views ### End motion of an empty spherical shell with a ball rolling on it's inner surface Let's picture an empty sperical shell in inter galactic space or beyond. Inside this shell, a ball is rolling on the inner surface. Because of friction and the centrifugal force the ball exerts on the ... 0 votes 1 answer 24 views ### What is the action pair of normal reaction in case of bike riding along a curved vertical wall I was reading about a situation in my brother’s physics textbook where a bike is riding along a curved vertical surface. It’s mentioned there that normal reaction provides the centripetal force and ... 2 votes 2 answers 104 views ### A simple proof that under Newtonian gravity rotating massive bodies are ellipsoids? Here is my attempt at deriving the shape of an idealized rotating massive body under Newtonian gravity, assuming that the gravity force points towards the center of mass and shape of the body is ... 1 vote 0 answers 23 views ### Does the Lagrange Point$L_3$exist in practice in the multi-body solar system? Lagrange Points ($L_1$through$L_5$) in a restricted 3-body system are well documented. Traditionally body 1 (M1) is the central object with a mass much greater than the other two objects. M2 is ... • 111 1 vote 1 answer 68 views ### What would happen if the Earth rotated at the rate required to achieve orbit at its radius? I.e ~7k m/s instead of ~460 m/s To achieve a circular orbit, you need to have a velocity of $$v = \sqrt{Gm/r}$$ which is about 7 km/s at the Earth’s radius, but the Earth’s rotational speed is only about 460 m/s (by taking the ... • 111 4 votes 1 answer 114 views ### Could we measure fictitious forces arising from rotation about an axis in a fourth spatial dimension? Two-dimensional creatures confined to a flat sheet that was uniformly rotating around an axis perpendicular to the sheet would have no trouble identifying that their sheet was rotating. They would be ... • 2,482 0 votes 2 answers 89 views ### Centripetal acceleration in rotational and translational motion How do you find the centripetal acceleration of any point on a body performing both rotational and translational motion. For example, in pure rolling if we find centripetal acceleration of the topmost ... 0 votes 1 answer 23 views ### What is the name of the instrument that separates substances using an electromagnetic field, similar to spectrography As far as I remember, the elements of the substance are passed across an electromagnetic field in such a way that they seperate as the electromagnetic field alters their trajectory. I also seem to ... 0 votes 1 answer 56 views ### Heavy mass vs light mass in circular motion If I have 2 spheres with different mass in a spinning Y shaped tube(no water is in the tube), which one will go higher because of inertia ... 0 votes 1 answer 36 views ### Angular momentum in a centrifuge Just a curiosity, centrifuges are ideally perfectly balanced, but can tolerate some level of imbalance. Is this due to the angular momentum of the rotor residing rapid oscillations in tilt? How would ... 0 votes 0 answers 37 views ### Central force problem: the basics In a central force problem, let$r'$mean the derivative of the radial distance with respect to time, then (m$r''$- mr$\theta''^2$)($\vec{r}$) = f($\vec{r}$) , the radial force. Please check if ... 7 votes 4 answers 835 views ### Gravitational force, centrifuge? So after going through 5 pages on google on why and how a centrifuge separates out particles of different densities, I still don't quite get this. If Galileos statement is right that force can be ... • 103 0 votes 4 answers 74 views ### How to understand what causes the centripetal force in this situation and what would be the direction of those forces and the centripetal acceleration [closed] A table with smooth horizontal surface is turning at an angular speed$ω$about its axis. A groove is made on the surface along the radius and a particle is gently placed at a distance$a$from the ... 0 votes 0 answers 29 views ### How large are the fictitious forces due to our orbit around the galactic center? When we are in a non-intertial system, this creates fictitious forces. Some well-known fictitious forces are the centrifugal and coriolis forces. Those are caused by the Earth's spin around its axis. ... • 606 3 votes 2 answers 134 views ### On a Torus World and the force upon inhabitants I am looking into torus worlds for fiction, and I know how to calculate the necessary speed to rotate, and necessary radius, for such a world to get a specific force of gravity. But what I am ... • 221 0 votes 1 answer 40 views ### Does the free surface of a liquid in a rotating frame depend on the viscosity? If we consider an incompressible, isothermal, stationary Newtonian flow (density ρ =const, viscosity μ =const), is it true that the form of the parabolic free surface in a rotating frame (constant ... • 45 2 votes 3 answers 193 views ### Centrifugal force effect in a rotating frame of reference If the centrepital force doesn't exist in a rotating frame of reference, then in this frame perspective, how can we explain why a ball tied to a string following a circular motion not to be pushed ... 2 votes 1 answer 41 views ### Can objects in space maintain a stable rotation spinning on two (or three) orthogonal axes simultaneously? Could a space station spin on two (or three) orthogonal axes at once and maintain a stable rotation? If the station was a hollow sphere, would the centripetal force be equal everywhere on the interior ... 0 votes 3 answers 51 views ### What is the extra kicks to accelerate a spacecraft during gravity assist? Suppose a spacecraft coming from behind a planet during a flyby, it gets a boost in speed and also change in direction of travel but where does this extra kicks come from? Now that I understand ... • 11.4k 1 vote 2 answers 79 views ### How would a game of (American) football work on a space station generating artificial gravity by using spin? [closed] Using rotation to generate artificial gravity is pretty common in sci-fi. I know the TV show "The Expanse" features it on the Mormon's vessel. I also remember a small-scale rotating space ... • 1,589 2 votes 3 answers 81 views ### Can this phenomenon be explained in ground frame? Suppose there is a disc which is rotating about its centre with constant angular velocity, the surface of disc is rough and there is a small block at some distance away from centre (at rest initially),... • 485 1 vote 1 answer 69 views ### How does Lagrange point$L_2$provide even meta-stability if centrifugal force isn't real? I recall hearing, perhaps colloquially, that a centrifugal force doesn't exist. It can be mistakenly felt but, it is not a real force. Given this, how does the$L_2$orbital point exist beyond the ... • 454 1 vote 2 answers 58 views ### What is causing this sign difference in the centrifugal term between Lagrangian and Hamiltonian formalism? [duplicate] Consider a central force problem of the form with the Lagrangian $$L(r, \theta, \dot{r}, \dot{\theta}) = \frac{1}{2} m \left( \dot{r}^2 + r^2 \dot{\theta}^2 \right) - V(r),$$ where$r = |\vec{x}|$. ... • 115 3 votes 2 answers 340 views ### Why does a mass move out when rotating? If a mass$m$is put on a stationary table, and then we start rotating the table counterclockwise, the mass will fall from the table, as can be seen in this video https://youtu.be/IOcrHOc23N4?t=187. ... • 283 0 votes 1 answer 36 views ### Liquid behavior in a rotating space station For a novel I'm writing, does a liquid's surface (e.g. coffee) slope upward in the opposite direction to the spin of the torus in a space station such as in 2001? I'm guessing it does due to the ... 2 votes 2 answers 198 views ### Maximum rotation speed of a planet of given mass and size What will be the limit of the rotation speed of a planet with given radius and size? will it depend on factors other than mass and size? Neutron stars are known to rotate at very high speeds but they ... 0 votes 0 answers 18 views ### Why does centrifugal force arise? [duplicate] We define centrifugal force as the outward force which a body experiences in circular motion. But i have few confusions in this topic: Why does the centrifugal force arise? If it acts on the same ... • 19 -1 votes 2 answers 100 views ### How is energy conserved in a system involving centrifugal force? Assuming there are two pieces of machines that are used to simulate kicking soccer balls. The machines are identical to each other except for the lengths of "leg" that is used to kick soccer ... • 113 2 votes 8 answers 131 views ### Centrifugal Force: Why is it so real even from non-inertial frame? [closed] I have thought about this for quite an amount of time. The questions: (1) Suppose we tie a ball on a merry go round with a string. Now, we observe the ball from the merry go round and from the ground. ... 0 votes 1 answer 130 views ### How to use Bernoulli equation in a rotating frame and is it always true that bernoulli will work? Lets say a fluid is rotating in a cylindrical shape container with every circular fluid streamline rotating with same$w$by some external mechanism, now imagine asking for pressure difference between ... • 485 7 votes 2 answers 116 views ### Can a rotating neutron star collapse to a black hole through a reduction in rotation? It is well known that non-rotating neutron stars cannot grow without bound, since an increase in mass causes a proportional increase in density, and accretion beyond a critical limit would cause it to ... 2 votes 2 answers 108 views ### Pseudoforces as seen by observer in a non-inertial frame Suppose, we have a car, that is accelerating with respect to an inertial frame, with an acceleration$a_c$. So, observers in the inertial frame can claim that there is a force$F_c=ma_c$acting on the ... • 453 0 votes 2 answers 145 views ### Force required to keep a car from sliding out of a curve I am a high school student trying to get an intuitive understanding of centripetal and centrifugal forces. I can calculate the correct solution but I don't understand the meaning of it. In class today ... 0 votes 1 answer 18 views ### Can you calculate the sedimentation rate of a coarse chemical suspension under gravity using a centrifuge? If the sedimentation rate can be determined for a coarse chemical suspension or a suspension containing large particles (i.e., particles with radii between$100$to$200 \mu m$) in a medium like ... 0 votes 1 answer 37 views ### How to use Centrifugal force in a rotating frame? Assume a stationary object (point object) on a smooth very large disc at a distance$r$from its axis perpendicular and passing through the centre. (No external forces apart from gravity and Normal ... • 1 5 votes 1 answer 54 views ### Inside an O'Neill cylinder, would a Pendulum's swing have any notable characteristics? Objects inside an O'Neill Cylinder would feel the Centrifugal effect, given by:$F=mω^2r$, and the Coriolis effect, given by:$F=d(mv)/dt\$, as well as air friction from air under the same effects. At ... 