Why is Centrifugal force “not real”? I remember my physics teacher in high school pushing that idea and understanding why back then, but I do not remember now. I also forgot so much about physics in general that a simple would be much appreciated!

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Why is Centrifugal force “not real”? I remember my physics teacher in high school pushing that idea and understanding why back then, but I do not remember now. I also forgot so much about physics in general that a simple would be much appreciated!

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66 Answers

Anonymous 0 Comments

Just to add to the other answers, yes, it only appears in a non-inertial reference frame.

You know what else is a fictitious force by that definition?

Gravity.

The sensation of gravity is the ground pushing you up to stop you following a “geodesic” (a path under free fall) to the centre of the Earth.

Astronauts on the ISS are in free fall, and thus in a pretty much inertial reference frame.

Whether a force is fictitious or not is kind of overblown IMO.

Anonymous 0 Comments

No, its fully real, problem people are digging into semantics too much.
is centrifugal force a force? No, it is not, it is a byproduct of mass moving at a velocity, changing direction fast enough for the mass to not be affected by things such as gravity.
Centrifugal force is real, its just not a force like the electromagnetic force.

Anonymous 0 Comments

Just to add to the other answers, yes, it only appears in a non-inertial reference frame.

You know what else is a fictitious force by that definition?

Gravity.

The sensation of gravity is the ground pushing you up to stop you following a “geodesic” (a path under free fall) to the centre of the Earth.

Astronauts on the ISS are in free fall, and thus in a pretty much inertial reference frame.

Whether a force is fictitious or not is kind of overblown IMO.

Anonymous 0 Comments

No, its fully real, problem people are digging into semantics too much.
is centrifugal force a force? No, it is not, it is a byproduct of mass moving at a velocity, changing direction fast enough for the mass to not be affected by things such as gravity.
Centrifugal force is real, its just not a force like the electromagnetic force.

Anonymous 0 Comments

Everyone’s commenting like “because it’s all in your head” etc, and I’m just looking at my centrifuge like… But it works… My samples aren’t changing because of the ~perception~ of force… Thanks for a thing I didn’t know I was confused about.

Anonymous 0 Comments

Everyone’s commenting like “because it’s all in your head” etc, and I’m just looking at my centrifuge like… But it works… My samples aren’t changing because of the ~perception~ of force… Thanks for a thing I didn’t know I was confused about.

Anonymous 0 Comments

Everyone’s commenting like “because it’s all in your head” etc, and I’m just looking at my centrifuge like… But it works… My samples aren’t changing because of the ~perception~ of force… Thanks for a thing I didn’t know I was confused about.

Anonymous 0 Comments

The grade school and high school level physics are going to say that centrifugal forces are really just the centripetal force (the force holding something to the spinning body, generally towards the center) and inertia combined.

I do not quite understand why this is taught this way, because it makes understanding reference frames a bit harder, but I guess this is a case of telling little lies so that students understand bigger truths.

Once you get to reference frames, you will learn that there are inertial and non-inertial reference frames. A fictitious force can be thought of as a force that only appears to exist in a non-inertial reference frame.

If I can interject my own belief and observation here: “fictitious” forces should be treated much like “imaginary” numbers should be treated. The names indicate a certain disdain as well as a fundamental misunderstanding of those forces/numbers, particularly when the respective areas were being developed.

Inertial reference frames are easier to deal with most of the time. The math is just easier. But there is nothing “wrong” with choosing a non-inertial reference frame, and can even be better for certain calculations.

And to throw yet another wrench into everything, General Relativity mixes things up by basically forcing things to be both inertial (locally) and non-inertial (globally) at the same time.

So do not think of centrifugal forces as not existing at all. Rather, they do not exist in an inertial reference frame, and physicists prefer to work with inertial frames.

Anonymous 0 Comments

The grade school and high school level physics are going to say that centrifugal forces are really just the centripetal force (the force holding something to the spinning body, generally towards the center) and inertia combined.

I do not quite understand why this is taught this way, because it makes understanding reference frames a bit harder, but I guess this is a case of telling little lies so that students understand bigger truths.

Once you get to reference frames, you will learn that there are inertial and non-inertial reference frames. A fictitious force can be thought of as a force that only appears to exist in a non-inertial reference frame.

If I can interject my own belief and observation here: “fictitious” forces should be treated much like “imaginary” numbers should be treated. The names indicate a certain disdain as well as a fundamental misunderstanding of those forces/numbers, particularly when the respective areas were being developed.

Inertial reference frames are easier to deal with most of the time. The math is just easier. But there is nothing “wrong” with choosing a non-inertial reference frame, and can even be better for certain calculations.

And to throw yet another wrench into everything, General Relativity mixes things up by basically forcing things to be both inertial (locally) and non-inertial (globally) at the same time.

So do not think of centrifugal forces as not existing at all. Rather, they do not exist in an inertial reference frame, and physicists prefer to work with inertial frames.

Anonymous 0 Comments

The grade school and high school level physics are going to say that centrifugal forces are really just the centripetal force (the force holding something to the spinning body, generally towards the center) and inertia combined.

I do not quite understand why this is taught this way, because it makes understanding reference frames a bit harder, but I guess this is a case of telling little lies so that students understand bigger truths.

Once you get to reference frames, you will learn that there are inertial and non-inertial reference frames. A fictitious force can be thought of as a force that only appears to exist in a non-inertial reference frame.

If I can interject my own belief and observation here: “fictitious” forces should be treated much like “imaginary” numbers should be treated. The names indicate a certain disdain as well as a fundamental misunderstanding of those forces/numbers, particularly when the respective areas were being developed.

Inertial reference frames are easier to deal with most of the time. The math is just easier. But there is nothing “wrong” with choosing a non-inertial reference frame, and can even be better for certain calculations.

And to throw yet another wrench into everything, General Relativity mixes things up by basically forcing things to be both inertial (locally) and non-inertial (globally) at the same time.

So do not think of centrifugal forces as not existing at all. Rather, they do not exist in an inertial reference frame, and physicists prefer to work with inertial frames.