Visualization of the Coriolis and centrifugal forces

A visual demonstration of the effects of the Coriolis and Centrifugal forces.

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This clip demonstrates the effects of the Coriolis and Centrifugal forces, by viewing various scenes from both rotating and stationary cameras. (The Coriolis force is also known as the Coriolis effect).

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The first example shows a cannon fixed to a rotating disc. The cannonballs
fly in straight lines since once shot no force acts on them. When
this scene is viewed from the disc's frame of reference (i.e., as would
be seen by a viewer that stands on the disc) the cannonballs seem to
fly in a curved path. This demonstrates that in a rotating frame of reference
one must take into account the Coriolis and Centrifugal forces.
(Read more about them in Wikipedia:
http://en.wikipedia.org/wiki/Centrifu...,
http://en.wikipedia.org/wiki/Coriolis...)

The second example shows a pendulum swinging over a rotating disc.
A pendulum swinging through a small angle approximates what is called "harmonic motion"
in which the ball is pulled to the center by a force proportional to
its distance to the center. In the pendulum, the string exerts a force
whose vertical component balances gravity and the horizontal component
(shown in the clip) causes the harmonic motion (approximately).
The disc and the pendulum has the same period,
meaning both complete a cycle at the same time.

When viewed from the disc's frame of reference the centrifugal and Coriolis
forces appear yet again. This time the centrifugal force balances
the string's horizontal component. This is because the centrifugal force is
also proportional to the distance from the center but pushing outward instead
of inward. The equal periods make the factor of proportion the same for both.
This leaves the Coriolis force alone to act on the ball. Since it is always
perpendicular to the object's path, this creates a perfectly circular path.

Finally, we decrease the pendulum's period to be 2/3 of the disc's period.
Now the centrifugal force no longer balances that of the string and the
motion becomes more complicated.

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• Category

  Science & Technology

[Fernando Dall'Agnol]

Beautiful work man! What applicative is that? How do you progressively change the referential frame? Keep doing it. Cheers.

[udiprod]

Thanks! I use a 3d animation tool called Maya to create all my videos. Reference frames are a basic ingredient in 3d animation tools, and you have a fine control on how they move and/or rotate, so creating such effects is really easy.

[Denis Hoste]

In this case, v would be of constant magnitude in constant direction, and so would w, thus making a_cor a constant. Am I right, and are you thus using another frame of reference than the world frame, or am I wrong?

I could really use some help on this, don't just tell me I'm wrong if I'm wrong, but please correct me if I'm wrong.

[udiprod]

In a non-rotating frame of reference, the w vector you mention would be zero so Coriolis force is also zero. Therefore Coriolis force only occurs in rotating frames of references. The video shows both: example 1 is first shown in the world (non-rotating) frame of reference, where no forces act on the balls, and then in the disc's (rotating) frame of reference, where Coriolis force bends their path. In example 2 also both frame of reference are shown (follow the titles)

[edansw]

doesn't the canon gives the cannonballs a beginning horizon speed?

[udiprod]

The important thing is that the balls move in straight lines because no forces act on them. If the cannon was placed on the rim

the balls would indeed have another component to their speed,

causing this line to be slanted with respect to the cannon at the time

the ball is fired, but it would still be straight. However, the cannon is in the middle so even this doesn't happen.

[antediluvian99]

That was fuckin majestic.

[udiprod]

This is a tricky question that combines physics and philosophy. Classical physics thought that physical laws only apply for a stationary point if view. In this sense, movements observed by a moving observer are not real physical movements, though philosophers may still claim they are real for this observer. Later, Relativity has shown there's no one single stationary point of view, which seem to strenghen a philosophical view that whatever you observe is real enough for you.

[Willoughby Krenzteinburg]

Mr. Myhre did not intend for you to replace the current concept of inertia with the one he proposes in his book. It is a philosophical and non-scientific explanation WHY inertia is a property of matter. He does not imply that the fundamental nature of inertia should change, because it shouldn't. Inertia is a property of matter that is its resistance to acceleration. His book does not deny this. It just, AGAIN, philosophically and NON-SCIENTIFICALLY explains WHY inertia is what it is. Ok?

[Willoughby Krenzteinburg]

I have indeed read this book, and I find it very interesting. One thing I must point out is that Guy Cavet Myhre believed what science says inertia is. He does not disagree with the concept of inertia per say; he is merely giving a philosophical approach to the concept. Another important point is that he was NOT a scientist. He was a pilot, a chef, a computer science teacher. Not a scientists by any measure. Science was a hobby for him, and he introduces some fine mind experiments.

[Willoughby Krenzteinburg]

There is really no point in arguing this. You're simply wrong. The concept of inertia was explained a few hundred years ago, and it has been verified so many times that it is second-hand knowledge for most people. Your claim about inertia is absurd as it is very easy to understand the concept. Inertia is a body's resistance to acceleration, and it is quantitively equivelant to its mass. This is basic fundamental physics.

[Willoughby Krenzteinburg]

It is not a prediction. Like I said, it is a property of matter that is very easily demonstrated. For example, gravity accelerates all objects at the same rate (from the same location). At the surface, that rate is about 9.8 m/s². The force of gravity is directly proportional to the mass of the object. The force on a 10 kg ball is ten times greater than the force on a 1 kg ball, yet they both accelerate at 9.8m/s². The reason for this is that a 10kg ball also has ten times the inertia.

[Ozan Bayrak]

I advice you to read ''Inertia is Gravity'' book of Guy Cavet Myhre.

[Ozan Bayrak]

''What is Inertia?Somethings inside the matter.''Do you think this is a good explanation?I don't think so,only a prediciton,this is not an explanation about inertia.

[Willoughby Krenzteinburg]

Inertia is a property of matter. It is the quantitive measure of the amount of mass an object has, and it is the objects resistance to change in motion. Inertia is NOT gravity. Inertia is NOT a force. Inertia is NOT a vector quantity. It is not based on far stars and galaxies. It is easier to push a ping pong ball than it is to push a bowling ball because the bowling ball has more mass, so it also has more inertia. A bowling ball resists change to motion more than a ping pong ball.

[Nelson Garcia]

STOP FUCKING MY BRAIN WITH ALL YOUR SCIENCE!