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0nakayama 2023/02/18 09:14 　5345view

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Michelson-Morley Experiment

It (done in air) is nonsense. In air, light is propagated at c/n. So, the result of M-M experiment (done in air) is only natural.

In a book "Theory of Relativity" by Pauli, W 1958, it's written as follows (quoted from English version ; in 1-6). "Rather should one say that for an observer moving with medium, light is propagated as usual with velocity c/n in all directions".

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174中山 2024/11/28 15:56

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Equivalence Principle

We can say that we can quantitatively grasp both gravity and inertial force. However, we cannot qualitatively grasp them. Do we have the right to preach equivalence principle ?

In fact, perhaps equivalence principle can be directly denied.

173中山 2024/11/22 09:33

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About Gravity

For free falling, pearl necklace would be a better thought experiment than elevator. There will be other examples too. A real example is Comet Shoemaker-Levy 9, which fell on Jupiter in 1994.

The conventional theory of Mercury's perihelion is poor. Also, Newton's shell theorem should be reconsidered.

172中山 2024/11/18 11:45

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Free Falling (Again)

Formula for gravity, G mM/r^2, and formula for inertial force, ma, are acting on pearl necklace. Gravity acts on each pearl with the magnitude indicated by the formula.

It is inevitable that gravity and inertial force cancel each other out totally (apparent) at a specific mass point.

171中山 2024/11/15 14:09

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Free Falling

Pearl necklace is falling freely in a vertical line. Gravity acting on each pearl is mM/r^2, and inertial force is ma. Mass of the string holding pearls is zero.

This post does not refer to equivalence principle.

170中山 2024/11/13 10:18

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Free Falling

On a celestial body below, two elevator cabins the same are falling freely. They are lined up one above the other and connected by a long string. Is some point on the string local inertial frame ?

169中山 2024/11/07 12:48

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Second Cosmic Velocity (question)

Kepler's third law states that orbital speed of a planet depends on radius of its orbit (if orbit is perfect circle). However, formula for second cosmic velocity is depends on radius of Earth. Are these two compatible ?

168中山 2024/11/01 11:12

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Free falling

The two, gravity and inertial force can be expressed as force vectors. So, it is possible that the two cancel each other out in a free-falling elevator (as a phenomenon).

However, free falling is only one phase in which two vectors interact. There is no reason why free falling should be treated as something special.

167中山 2024/10/31 11:55

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Equivalence Principle

A body of mass m is placed on flat surface (without friction). String pulls this body to the right with tension ma. The body accelerates to the right, and inertial force ma acts to the left. Magnitude of tension and inertial force are equal. This is as shown by Newton's third law of motion.

The fact that gravity and inertial force are equal (in total) in a free-falling elevator is probably due to Newton's third law of motion.

166中山 2024/10/29 12:23

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Free Falling

An elevator cabin is in free falling. Elevator is rigid body consisting of the same mass points with mass m. Each mass point has the same acceleration. The same force acting on each mass point is ma.

There is no word equivalence principle in above explanation or any of the following. In fact, there should be no word equivalence principle.

165中山 2024/10/20 17:30

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Equivalence Principle (again)

Magnitude of gravity acting on a body (mass m) is GmM/r^2, and magnitude of inertial force is ma. For vectors of two forces, to cancel each other out is not prohibited (as phenomenon). In free-falling elevator, two forces cancel each other out (as phenomenon) in one local area totally and in other local areas partially.

As above formulas show, two forces are different. Real elevator do not support equivalence principle.

164中山 2024/10/15 08:13

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Equivalence Principle

On state of being of vectors of gravity (attraction) and inertial force, there will be no restrictions. Therefore, vector of two forces will be possible to be compensate and nothing special happens. Like an elevator in free fall.

Force acting on us on surface of Earth is resultant force of gravity (attraction) and centrifugal force. On surface (solid or liquid) of planets of solar system, gravity (attraction), speed of planet's rotation, and centrifugal force all is various. Equivalence principle is unacceptable.

163中山 2024/10/11 08:03

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About Gravity

"Resultant force of attraction and centrifugal force of Earth is the true nature of gravity." This is cited from a website. However, I think that attraction in this citation is the true nature of gravity. This citation is evasive and delegate.

Equivalence principle is unacceptable. One reason is that, I can't recall ever seeing universal gravitational constant mentioned on inertial force.

162中山 2024/10/09 11:21

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About Gravity

Following claims : Newton's spherical shell theorem, Perihelion shift of Mercury (claimed before relativity, before 1905) are unacceptable. My veiw are posted into some web-sites in English.

Also in relativity, I find no acceptable claim regarding gravity (equivalence principle is unacceptable). And I posted objections (that I can) to relativity's claims regarding gravity.

161中山 2024/10/03 16:09

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Centrifugal Force is not Fictitious

Centrifugal force that is accompanied by rotational motion is inertial force, that is, real force or action. Reaction to it is a centripetal force (In case of hammer throwing wire, it can also be considered tension or tensile stress). Its form and magnitude do not vary no matter what frame it is viewed from.

The same is true for all curvilinear motion.

160名前を書き忘れた受験生 2024/10/03 14:35

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文法は簡単だけど自分の語彙力の無さに幻滅

159中山 2024/10/03 13:46

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Centrifugal Force is not Fictitious (again)

On a plane, two rods cross each other (without friction) and rotate around intersection point. This basic form can be transformed as follows.
1) Body of mass m is attached to both ends of one rod. Body of mass 2m is attached to both ends of the other rod. Mass of rods is assumed to be zero.
2) Body of mass m is attached to each of four ends of two rods. Length of one rod is a, and length of the other is 2a. Mass of rods is assumed to be zero.
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Centrifugal force and tension acting on rods are real forces, not fictitious. From any frame.

158中山 2024/09/02 12:16

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Acceleration and Non-Acceleration

A body is being pulled by strings from the left and right. Tension in the strings is the same, ma. The same body is being pulled by one string from the left and by two strings from the right. Tension in all three strings is the same, ma. Let the body in two figures be A and B.

Are A seen from B and B seen from A symmetrical ? No, that's not, because the internal stresses in body A and B are different.

157中山 2024/08/29 09:05

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Inertial force is not Fictitious (rewritten)

A spaceship is moving horizontally with uniform acceleration. Inside the spaceship, a body m is pushing against the rear wall. This force is action, and is inertial force. As reaction, and as normal force, the rear wall pushes back against the body. Magnitude of the two is ma.

Above explanation should be valid for one inside and outside the spaceship. Inertial force will be a real force for everyone, and will not be fictitious.

156中山 2024/08/24 10:06

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Accelerating Frame and Non-Accelerating frame (fragmentary)

◎ An observer in a passenger car accelerating at a uniform speed will see everything in the car as at rest. What if g is large ?
◎ A website says that equiliblium of forces are only for framess that are at rest or in uniform linear motion.
◎ The difference between accelerating frame and non-accelerating frame is crucial. But we continue to turn away from to it. This is physics.
◎ A string stretches horizontally inside the cabin of a spaceship moving to the right with a uniform acceleration. The right end of the string is fixed to the right inner wall of the cabin, and the left end is fixed to body m, which is floating inside the cabin. The string has a tension ma (ignore the mass of string). Both m and a are specific values.

m and a will be the same for one inside and outside the ship.

155中山 2024/08/20 12:19

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Inertial Force is not Fictitious (rewritten)

Inertial force of a body moving in uniformly accelerated linear motion is based on m and a. There can be no denying. In addition, ma = F. In short, inertial force is not fictitious.

154中山 2024/08/18 15:17

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Inertial Force is not Fictitious

In actual examples of action and reaction in Newton’s third law of motion, sometimes, it is unclear which is action and which is reaction. But it must be clear that inertial force can be either of the two. Then inertial force must be real force. For everyone.

In the well-known formula F = ma, which is inertial force ? It can be ma. Then inertial force must be real force. For everyone.

153中山 2024/08/17 13:32

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Asking (for my post 152)

Please add a word "horizontally" after the word "stretches" in the second line of my post.

152中山 2024/08/15 10:42

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Inertial Force is not Fictitious (rewritten)

Inside the cabin of a spaceship moving with uniform acceleration to the right, a string stretches. Right end of the string is tied to the right inner wall of the cabin, and left end is tied to a body m, floating inside the cabin. There is tension ma in the string (ignore mass of the string).

This physica fact and its explanation must be the same for one inside and outside the spaceship.

151中山 2024/08/11 09:00

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Compound Nouns

Gravitational acceleration, Local inertial frame, Inertial mass, Gravitational mass. Although, there are a few nouns, because of my shallow ness. However, probably or clearly, these will be forcible.

150中山 2024/08/06 09:54

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Statics or Dynamics?

A point (point of action) is pulled left and right by strings with a vector F, creating balance. Can the force on the right be considered an inertial force ? At right end of the right string, a body with mass m is placed. In other words, tension ma is acting on the right string. In this pictere, the whole is moving to the left with a uniform acceleration.

Note: A website says, "Do not bring force into the cause of the motion (into its change also)."

149中山 2024/08/03 09:30

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Inertial Force is not Fictitious (rewritten)

An body m is suspended by a string from the center of the ceiling of a passenger car. If the passenger car is accelerated to the right, string and body will tilt downward to the left. But, what if the passenger car is jerk-moving? The inclination of string and body will continue to increase, the tension in the string will increase, and eventually the string will break.

These situations and explanations of the situation must be the same for one inside and outside the passenger car. Inertial force is not a fictitious force for one inside and outside the car. Inertial force in this case is the action, and the reaction is the tension in the string.

148中山 2024/07/19 13:36

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Inertial Force is not Fictitious (rewritten)

By a string, a body of mass m is hanging from the ceiling in the center of the passenger car. Body and the string are perpendicular. Next, the passenger car begins to accelerate to the right. Body and the string tilt to the left. This acceleration is usually constant. However, if an external force F continues to grow as time passes, the inclination of body and the string also continues to grow. This varying is the same for one inside and outside the passenger car. And, the tension of the string, which is a reaction to the inertial force will be the same to the two also (and if the string breaks, it will be the same to the two also).

147名前を書き忘れた受験生 2024/07/09 17:31

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Allow you to add.

146中山 2024/07/09 09:30

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Speed **of Starlight (Supplement)

Allow me to add to 145. When the glass cube moves left and right....
Inside the glass, c/n is constant, and the other two are variable
Just before entering the glass, λ is constant, and the other two are variable
Just after leaving the glass, c is constant, and the other two are variable

145中山 2024/06/15 10:10

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Speed **of Starlight

A glass cube is floating horizontally in outer space. Two rays of starlight coming from the left and right are passing through the glass horizontally. Below is the difference between the two rays of light as seen from viewpoint of the glass (difference in formula v = f λ).

Difference inside the glass 　　　　　　　　　　　c/n = c/n 　　f ≠ f 　 λ ≠ λ
Difference just before entering the glass　　　c ≠ c 　　　　 f ≠ f 　 λ = λ
Difference just after leaving the glass　　　 　c = c 　 　　 f ≠ f 　 λ ≠ λ