99 votes
Accepted

How does tilting a bike make it turn sharper?

It is actually not the tilting that causes more turning. You could in theory turn just as much while being straight up by just turning your steering wheel. But if you do that straight up, you fall. ...
Steeven's user avatar
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67 votes
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How does rotational "artificial gravity" differ from normal gravity?

I think a rotating frame would have both a centrifugal force, mimicking gravity, and what is called a Coriolis force. So, for example, if you would throw a ball straight up in the air in the rotating ...
Eric David Kramer's user avatar
63 votes

If the ground's normal force cancels gravity, how does a person keep rotating with the Earth?

Actually, this is rather insightful. The normal force from the ground does not quite cancel out the effect of gravity. The difference between them is precisely the centripetal force that keeps you ...
David Z's user avatar
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62 votes
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Does artificial gravity based on centrifugal force stop working if you jump off the ground?

Now, the question: if, while being inside a rotating space station, astronaut would jump really high, wouldn't he then experience zero gravity until he again will touch some part (wall or floor) of ...
knzhou's user avatar
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59 votes
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How can the centripetal force lead to objects flying apart?

In the lab frame of reference, you need to reverse the question - don't ask yourself what pulls the particles apart but what keeps them together. By Newton's laws, everything on which no force acts ...
ACuriousMind's user avatar
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58 votes
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What is the reason behind water not falling from a bucket at the top of loop?

It is a common misconception that objects have to move in the direction of the force. This is false; the acceleration points in the direction of the force. This means the change in velocity points in ...
BioPhysicist's user avatar
57 votes

What is the reason behind water not falling from a bucket at the top of loop?

The water does fall. It just doesn't fall faster than the bucket. By pulling on the bucket, you keep it around the (also falling) water.
BowlOfRed's user avatar
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56 votes

Does centrifugal force stiffen a rotating blade?

For simplicity, let's model the helicopter blade as a simple massless beam with a point mass at the end. When there is no gravity, the beam will be straight. We now introduce a force to the beam tip,...
DeltaLima's user avatar
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49 votes
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Why would a spinning space station create a centrifugal force on an astronaut rather than simply spinning around him/her?

Put a stationary astronaut in a small room inside a large spinning cylinder. After an instant walls of that room will hit him, and suddenly he will have the same velocity as the room. Due to angular ...
Mikael Kuisma's user avatar
44 votes
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If an object moving in a circle experiences centripetal force, then doesn't it also experience centrifugal force, because of Newton's third law?

This is a common misinterpretation of Newton's third law, often stated as "to every action, there's an equal and opposite reaction." As you surmise, "action" and "reaction" refer to forces. However, ...
Ben51's user avatar
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40 votes

Why would a spinning space station create a centrifugal force on an astronaut rather than simply spinning around him/her?

You are correct in that if the astronaut is undergoing no translational or rotational motion relative to the centre of rotation of the space station the astronaut will feel weightless as in diagram $A$...
Farcher's user avatar
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40 votes
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Why is centrifugal force called fictitious?

I disagree that you feel centrifugal force. A person in a centrifuge actually feels their reaction to the centripetal force. If you sit in a car that is subject to harsh acceleration, you 'feel' as if ...
Marco Ocram's user avatar
38 votes
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If centrifugal force is a pseudo-force then why we can observe its effects outside of rotating frame?

When objects fly off a spinning table, from an external reference frame they simply stop travelling in circles. At the point of "unsticking" they do not accelerate radially outwards from the centre of ...
Guy Inchbald's user avatar
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38 votes

Is Earth really flattened at the poles because of centrifugal force?

The description from an interial frame is that the bits of the Earth at the equator are moving faster than those near the poles, so they have more kinetic energy, and thus they are a bit farther away ...
Javier's user avatar
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37 votes
Accepted

Weightlessness in Satellites

The statement: The Gravitational Pull is counterbalanced by the Centripetal Force is rubbish. The satellite undergoes a centripetal acceleration because it is acted on by the gravitation force. ...
Farcher's user avatar
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36 votes

Why is centrifugal force called fictitious?

A force is fictitious if it doesn't obey Newton's three laws of motion. Recall Newton's first law: The first law states that an object at rest will stay at rest, and an object in motion will stay in ...
AccidentalTaylorExpansion's user avatar
33 votes

How does rotational "artificial gravity" differ from normal gravity?

I'm speculating, but the speculation is based on actual physics :). Your physical experience of gravity on a planet and artificial gravity at the outside of a rotating wheel might be different based ...
msouth's user avatar
  • 441
30 votes

Why do we still use pseudo forces?

In practice, in newtonian mechanics, pseudoforces are used, because they're simple and convenient. At the end of the day, they're only inertial terms that you're "disguising" as forces. You ...
Miyase's user avatar
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26 votes

How does tilting a bike make it turn sharper?

Notice that when the biker tilts more, the torque due to gravity increases(taking pivot to be any point other than point of contact or center of mass as then centrifugal forces would be needed to ...
Tausif Hossain's user avatar
24 votes

How does tilting a bike make it turn sharper?

This is called countersteering. see an in-depth physics explanation here. As you turn, the top part of the bike wants to go keep going straight (because of inertia), whereas the wheels are bound to ...
Sklivvz's user avatar
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23 votes

Why would a spinning space station create a centrifugal force on an astronaut rather than simply spinning around him/her?

If there is no atmosphere, and the station is a relatively smooth cylinder, you can indeed float there as the exterior walls spin around you (in the middle, or just above a wall, or anywhere). Now, ...
Yakk's user avatar
  • 4,273
22 votes

How can the centripetal force lead to objects flying apart?

Try to imagine, instead of a big stone, a big plate. On top, you fill the plate with sand. Now you start spinning the plate. What's going to happen to the sand? The sand is going to leave the plate ...
Svalorzen's user avatar
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22 votes
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If centrifugal forces are fictitious, then isn't gravitational force also fictitious?

The best way to avoid this kind of confusion is to start from the beginning in a purely Newtonian description of the motion, i.e., working in an inertial frame. Only after understanding the situation ...
GiorgioP-DoomsdayClockIsAt-90's user avatar
21 votes
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Would you feel Centrifugal Force without Friction?

The answer here is yes. In the reference frame of the spinning torus, the object in the tube receives the expected amount of centrifugal force towards the outer rim ... but, it also receives a ...
Justin L.'s user avatar
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21 votes

Does centrifugal force stiffen a rotating blade?

My counter argument is quite simple. A force can only affect the stiffness of a blade if it changes the physical characteristics of the blade and such force(s) can only be exerted as a result of ...
alephzero's user avatar
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21 votes
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Earth as a perfect sphere and an object trying to stand still

Indeed, you need friction. Otherwise this object will slide to equator just as you expect. In fact, all the objects will slide there to form equatorial bulge and eventually the sphere will be turned ...
FiatLux's user avatar
  • 336
21 votes

Does artificial gravity based on centrifugal force stop working if you jump off the ground?

If you jump then you are in free fall, apart from air resistance, so you are weightless. This holds for any jump. For a brief moment, you experience zero gravity!
my2cts's user avatar
  • 23.8k
21 votes

Why is centrifugal force called fictitious?

According to the basic Newtonian formulation of mechanics, "real" forces come in couples: a force (action) and its reaction acting on the source of the action. Furthermore "real" ...
Valter Moretti's user avatar
20 votes
Accepted

How exactly does artificial gravity work?

If you were in a zero-gravity environment (e.g., in earth orbit or in a coasting trajectory en route to Mars), alone in your space suit, you would feel no gravity. If a big pipe were placed around ...
S. McGrew's user avatar
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