Many ask in the comments: But isn't this Centrifugal force?

On centripetal motion:
(Google Definition: a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.)

By definition, all accelerations are due to a force. Yes? f=ma. So, for there to be a force, there must mathematically be both an "m" and an "a".

So, we need to see what object is accelerating what mass where.  Can we agree the floor is pushing him inward - toward the center? (otherwise he would fly out). He NEEDS the floor. If we were to remove that floor, he would fly out.

So, the floor is a necessary part of this system - and the floor force is inward. And the force he enjoys has the same sensation of gravity when we stand on the earth. And since the ground is in our way, we end up with a balanced force we call weight. (weight = m × 9.8 m/s2)

On centrifugal force:
(Google Definition: an *apparent* force that acts OUTWARD on a body moving around a center, arising from the body's inertia.)

Let's remove Frank Poole's floor. When the floor is removed and Frank flies out into space... WHY does he fly out into space? Is there some PUSH or PULL sending him outward? No. Not the walls, floor, ceiling, air or gravity or any such thing is forcing him outward. Forces come from somewhere, some causal agent, a mover. And the floor is the only thing acting on him. And that floor is doing quite the opposite of throwing him OUTward. In fact, the floor is the VERY THING holding him IN.

So, the question remains. Without a floor, why does Frankie fly out into space?
Inertia. He is an object in motion that is aiming to remain in motion at the same speed and direction. Just like a tetherball or the earth in orbit - it's ready to fly off in a straight line at any given moment, but for gravity (or the string on the tetherball) holding them in. When Frank came down that ladder, the more he descended, the more the ladder began to progressively throw Frank outward. If you have ever been on a fast-moving carousel, the farther out you go, the harder you are thrown and have to fight against your own inertia to remain circular. Grease the carousel floor and your ride is over, or perhaps the ride is just beginning.

But can't we say, "So, INERTIA, is the force that throws Frank out?"

Except... inertia is NOT a force. It would turn physics on its head if inertia was a force. Inertia is a property of matter that resists all change. Inertia is the antithesis of force. Inertia battles against all forces with all their accelerations. That's the whole First Law of Motion. ("An object at rest... an object in motion... UNLESS...a...force...") Inertia is a proponent for the status quo. Inertia is to be overcome by force, not an ally of force. In Inertia-land, inertia would have all accelerations = zero. Nill. Nada.

Inertia is anti-acceleration and therefore anti-force. Therefore, inertia can't be listed as a true force.

Therefore, with inertia opposing accelerations:
If f=ma
And a=0
Therefore f=m0
Therefore f=0
Therefore, no force, outward or inward from inertia.

So, where does that leave Frank?

Let's return to the definition of Centrifugal Force - the pseudo-force. The stumbling block of physics students.
Centrifugal Force: "An APPARENT FORCE that acts outward on a body moving around a center, ARISING FROM the body's INERTIA." The definition binds force and inertia together, but as those two are in opposition, it is rightly called an "apparent" force. It is not what it seems - Centrifugal Force is not a true force.

This is why mainstream scientists reject that centrifugal force is a true force. To assert that centrifugal force is indeed a force, one will have to identify from where this force arose. Until there is an answer, centrifugal force will remain a fake force, much the same as simulated gravity is not truly gravity. The true culprit of both simulated gravity and centrifugal force is secretly Centripetal Force.

So, with the floor removed, Frank flies out *in spite of* any forces (1st Law), NOT *because of* forces (2nd Law).

Which returns us to Frank's floor. Frank's *inward*, center-pushing floor. The floor is the force source. And the force is inward, not outward. And this circles us right back to Centripetal Force, that puts inertia in opposition to the floor - in a perpetual balanced force pair of "Frank vs Floor" that simulates both gravity and weight.
So, once again, Frank enjoys Centripetal Force. Definition: Centripetal Force: "A force that acts on a body moving in a circular path and is directed toward the center around which the body is moving."

Hope this helps.
Here's another resource from West Texas AMU:
[ Ссылка ]

свернуть