|  |  |  |  |  |  |  |  |  |  |  | | SPHERICAL SHELL PROBLEM (SSP) SUMMARY The spherical shall problem (SSP) is a very simple and very important experiment of
Classical Physics. The problem (SSP) is a special (and simple) case of the “three bodies” problem. By solving this problem, which is done exclusively on the basis of Newtonian Mechanics, and assuming Newton¢s axiom on the equality of the inertial mass mi and the gravitational mass mg, (mi = mg), we formulate the fundamental law of the free fall of bodies.
Based on the fundamental law of the free fall of bodies, we can prove that: Gravitational fields never have the remarkable property of imparting all bodies with the same acceleration, regardless of their mass and their material constitution, as Galileo and Einstein mistakenly claim. See: http://www.tsolkas.gr/forums/tga6.jpg (Book: THE PRINCIPLE OF RELATIVITY, by A. EINSTEIN, H.A. LORENTZ, H. WEYL, H. MINKOWSKI).
Simply put, based on the fundamental law of the free fall of bodies, we can prove that: 1) The results of Galileo¢s experiment (the tower of Pisa experiment) are not theoretically correct, but empirically and approximately. 2) The “equivalence principle” (strong and weak) of the General Theory of Relativity is a completely false principle of Physics. SOLVING THE SPHERICAL SHELL PROBLEM (SSP)
Let us assume, Fig. 1, that we have a homogenous spherical shell, with a mass of m1 and a radius of Ro. | | |  | | | | Fig. 1 At the centre of the spherical shell m1, we place a point mass m2. At a distance h from the centre of the spherical shell m1, is a body of mass M. Note: Each one of masses m1, m2, M is considered a
totally solid body (i.e. not altered by the gravitational forces exercised between them). Obviously, the system of the two masses m1 and m2 (i.e. of the spherical shell m1 and the point mass m2) does not behave as a totally solid body of mass m1 + m2. We now perform, Fig. 1, our experiment in two phases (Phase I and Phase II), as follows: PHASE I: During this phase, and at the moment to = 0
, the point mass m2 is at the centre of the spherical shell m1 and the centre of the spherical shell m1 is at a distance h from the mass M. Also, during this phase (to = 0), the spherical shell m1, the point mass m2 and the mass M are motionless as to the inertial reference system S. In order words, at to = 0, we have õ1 = 0, õ2 = 0 and V = 0
, where õ1 is the velocity of mass m1, õ2 is the velocity of point mass m2 and V is the velocity of mass Ì. In order words, Velocities õ1 = 0, õ2 = 0, V = 0 obviously refer to the inertial reference system S. PHASE ÉÉ: During this phase, we allow, from a height h, the spherical shell m1 (with the point mass m2, which is at its
centre) to move freely under the influence of the force of universal attraction exercised between masses m1, m2 and Ì. Let us assume now that after a time t1 > 0 of free fall, the velocity of mass m1 is õ1 > 0, the velocity of point mass m2 is õ2 > 0 and the velocity of mass Ì is V > 0.
After what we discussed above, the critical question that emerges is this: QUESTION: During the performance of the spherical shell experiment, Fig. 1, and at the moment t1 > 0 (Phase ÉÉ) of free fall, will the point mass m2 remain at the centre of the spherical shell m1 where it was originally (to = 0) placed, or will it move from the centre of the spherical shell m1?
In accordance with the proof (which follows), the answer to that question is: In the spherical shell problem, Fig. 1: 1. When the two masses m1 and m2 are equal (m1 = m2), then, at the moment t1 > 0 the point mass m2 will be at the centre of the spherical shell m1. 2.Conversely, if the two masses m1 and m2 are not equal (
m1 ≠ m2), then, at the moment t1 > 0 the point mass m2 will move from the centre of the spherical shell m1. PROOF Let us assume, Fig.1, that at the moment t1 > 0 the point mass m2 is with the spherical shell m1 and the distance of mass m1 (i.e. the centre of the spherical shell m1
) from the centre of mass Ì is h1 and the distance of point mass m2 from the centre of mass Ì is h2. If we now apply to the system of the three masses m1, m2, M at the moment t1 > 0: 1. The principle of conservation of energy, and 2. The principle of conservation of momentum, we have relations: | | | |  | | | |
In relations (1) the numbers õ1, õ2, V, h1, h2, h are all considered positive numbers. Also, relations (1), can also be expressed as follows: | | | |  | |
 |  | | Posing now: |
 |  | | and  = ÌV relations (2) can be expressed as: |
 |  | | In relations (4) and (4.1), it is obviously: |
 |  | | where, |
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| From now on, relations (4) will be referred to as the basic relations of the spherical shell problem (SSP). As mentioned above, in relations (4), Ê can only have one of two values, i.e.: |
 |  |  | |  |  | |  | | | | Note: As we will see below:
For m1<m2, relations (4) are acceptable and relations (4.1) are rejected. For m1>m2, relations (4.1) are acceptable and relations (4) are rejected. Where, in cases (a) and (b) in relations (4) and (4.1), K>0. For m1=m2, relations (4) or relations (4.1) are acceptable. Where, in case (c) in relations (4) and (4.1), K=0.
RESEARCH ON THE SPHERICAL SHELL PROBLEM
In the spherical shell problem, let us take, e.g. relations (4) of the basic relations (4) and (4.1). Relations (4) yield: | | |  | |
 | resulting in: |
 |  | | Based, therefore, on relation (8), we can now formulate the following fundamental law: |
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | | LAW É In relation (8): When Ê = 0, then õ1 = õ2 and, conversely, when õ1 = õ2,
then Ê = 0. When Ê > 0, then õ1 > õ2 and, conversely, when õ1 > õ2, then Ê > 0.
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| | | | Law É, as described above, plays a very important part in
the research on the spherical shell problem, and especially in terms of basic relations (4) and (4.1). É. EQUAL MASSES In the spherical shell problem, Fig. 1, and in the event that the masses m1 and m2 are equal (m1 = m2), we will prove that: In relations (4), when the masses m1 and m2 are given, (m1 = m2), then õ1 ≠ õ2 can never apply.
Proof According to the problem, since when masses m1 and m2 are given (m1 = m2) õ1 ≠ õ2 can never apply, it means (correspondingly), that: When masses m1 and m2 are given m1 = m2 (9) then the only relation that applies is:
õ1 = õ2 (10) because õ1 ≠ õ2 and õ1 = õ2 are mutually exclusive, (only one or the other can apply). Hypothesis: Let us assume that relation (10) applies, then from relations (9) and (10), we have: m1õ1 = m2õ2 (11) m1õ1 – m2õ2 = 0 (12)
In addition, from relations (4), we have: | | | |  | | | | And relations (13) yield: | | | |  | | | | In addition, from relations (12) and (14) we have: | | | |  | | | | Because, according the data of the problem, m1 = m2, then, based on relation (9), relation (15) yields: | | |
|  | | | | Based on relation (16), relation (8) yields: |
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Relation (17) corroborates our hypothesis (õ1 = õ2). Subsequently, our hypothesis is correct. Our problem, therefore, has been proven. We have proven that: In relations (4), when masses m1 and m2 are given (m1 = m2), then õ1 ≠ õ2 can never apply, because we have proven that relation õ1 = õ2 always
applies. Therefore, the following relation will always apply: | | | |  | | | | where, in relation (18) m1 and m2, (m1 = m2) are the data of the problem, and õ1, õ2 (õ1 = õ2) are the conclusion. b) Conversely: In relations (4), when the velocities õ1 and õ2 are given (õ1 = õ2), then m1
≠m2 can never apply. Proof According to the problem, since when velocities õ1 and õ2, (õ1 = õ2) are given, m1 ≠ m2 can never apply, this means (correspondingly) that: When velocities õ1 and õ2 are given: õ1 = õ2 (18.1)
then the only relation that applies is: m1 = m2 (18.2) because m1 ≠ m2 and m1 = m2 are mutually exclusive, (only one or the other can apply). Hypothesis: Let us assume that relation (18.2) applies, then from relations (18.1) and (18.2), we have: m1õ1 = m2õ2
(18.3) m1õ1 – m2õ2 = 0 (18.4) But because relations (4) yield: | | | |  | | | | Then (as in case (a) above), relations (18.4) and (19), yield: | | | |  | | | | Ion addition, since according to the data of the problem õ1 = õ2
, relation (8) yields: Ê = 0 (21) Based on relation (21), relation (20) yields: | | |  | | | | Relation (22) corroborates our hypothesis (m1 = m2). Therefore our hypothesis is correct. Which means that our problem has been proven. We have proven that: In relations (4), when velocities õ1 and õ2 (õ1 = õ2) are given, then m1
≠ m2 can never apply, because we have proven that relation m1 = m2 always applies. Therefore, the following relation will always apply: | | | |  | | | | where, in relation (23) õ1 and õ2, (õ1 = õ2) are the data of the problem and m1, m2 (m1=m2) are the conclusion.
After what we discussed above, we can draw the following basic conclusion. | | | | CONCLUSION É In the spherical shell problem, Fig. 1, and in relations (4): a. When the masses m1 and m2 are given (m1 = m2), then the velocities õ1 and õ2 are always equal (õ1 = õ2) and, conversely, b. When the velocities õ1 and õ 2 are given (õ1 = õ2) then masses m1 and m2 are always equal (m 1 = m 2).
From conclusions (a) and (b) results the relation:

when, in relation (24), m1 = m2 and õ1 = õ2. Therefore, in accordance with relation (23.1), it emerges that: c. When the masses m1 and m2 are given (m1 ≠ m2) then the velocities õ1 and õ2 are always õ1 ≠ õ2
and, conversely, d. When the velocities õ1 and õ 2 are given (õ1 ≠ õ2), then masses m1 and m 2 are always m1 ≠ m2.
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 |  | | Based on the above conclusion, we can now formulate the following law: |
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | | LAW ÉÉ
In the spherical shell problem, when the two masses m1 and m2 are equal (m1 = m2), then: During the fall for of the equal masses m1 and m2 within the field of gravity of mass
Ì, then both masses m1 and m2 always fall with the same velocities õ1 and õ2, (õ1 = õ2) as per the inertial reference system S. m1 = m2 , õ1 = õ2 |
| | | | ÉÉ. UNEQUAL MASSES According to conclusion I (paragraph (c)) as above, when m1 ≠ m2, then õ1 ≠ õ2. In the spherical shell problem, Fig. 1, we will prove that: When masses m1 and m2 are given (m1 < m2), then õ1 < õ2 can never apply.
Proof According to the problem, since when masses m1 and m2 are given (m1 < m2) õ1 < õ2 can never apply, this means (correspondingly) that: When masses m1 and m2 are given, m1 < m2 (24.1)
then the only relation that applies is: õ1 > õ2 (24.2) because õ1 < õ2 and õ1 > õ2 are mutually exclusive, (only one or the other can apply). Hypothesis: Let us assume that relation (24.2) applies. If we solve the system of equations (3) for m1 and m2, we have:
| | | |  | | | |
Since, according to the data of the problem: m1 < m2 (26) then relations (25) and (26) yield: | | |  | | | | In addition, since according to conclusion É, when m1 ≠ m2 then õ1 ≠ õ2, this means that: In relations (25), when m1 < m2 then:
õ1 ≠ õ2 (27.1) Therefore, relation (27), (which results from relations (25)) will always be õ1 ≠ õ2, i.e.: õ1 - õ2 > 0 (27.2) according to the hypothesis. Based, therefore, on relation (27.2), relation (27) yields: (Âõ1 – Á) õ1 > (Á – Âõ2)õ1
Â(õ12 + õ22) > Á(õ1 + õ2) (27.3) In relation (27.3), if we replace Á and  as these result from relations (3), we have: | | | |  | | | | In relation (27.4), since, according to the data of the problem: m1 < m2 i.e.: m2 – m1 > 0 (27.5)
relation (27.4) is verified only when: õ1 – õ2 > 0 i.e.: õ1 > õ2 (27.6) Relation (27.6) corroborates our hypothesis õ1 > õ2 . Therefore, our hypothesis is correct. Which means our problem has been proven. We have proven that: In the spherical shell problem, Fig. 1, when the masses m1 and m2 are given (m1 < m2) then õ1 < õ2 can never apply, because we have proven that relation õ1 > õ2 always applies.
Therefore, the following relations will always apply: | | | |  | |
 |  | | where, in relations (27.7) m1 < m2 are the data of the problem and õ1>õ2 are the conclusion.
Conversely: Based on relations (21) and in the same way we described above, we can prove that: When the data is õ1 > õ2, then relation m1 > m2 can never apply. Therefore, relation m1 < m2 must apply, because m1 > m2 and m1 < m2 are mutually exclusive. In that case, we are lead back to the same relation: (õ1 – õ2) (m2 – m1)
> 0 (a) where the data in relation (a) are õ1 > õ2, i.e. õ1 – õ2 > 0. SUMMARY 1. In accordance with the above proof: When the data is m1 < m2, then õ1 > õ2 and conversely, when the data is õ1 > õ2, then m1 < m2, i.e. the following relation applies:
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 | | | | 2. Therefore, according to relation (b): When the data given is m1 > m2, then õ1 < õ2 will apply and, conversely, when the data given is õ1 < õ2, then m1 > m2, i.e. the following relation applies:
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CONCLUSION ÉÉ In the spherical shell problem, Fig. 1: a. When m1 < m2, then õ1 > õ2 (in accordance with relation (b), as above). b. When m1 > m2, then õ1 < õ2 (in accordance with relation (c), as above).
In other words, as demonstrated by the above cases (a) and (b), a higher velocity corresponds to the smaller mass, and a lower velocity corresponds to the larger mass. |
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After what we described above, we can now formulate the following basic law. | | | | LAW ÉÉÉ In the spherical shell problem, Fig. 1, when the two masses m1 and m2 are unequal
(m1 < m2), then: During the free fall of these unequal masses m1 and m2 within the field of gravity of mass Ì, the smaller mass m1 falls with a higher velocity õ1, while, conversely, the larger mass m2, falls with a lower velocity õ2, (õ1 > õ2), as per the inertial reference system S. m1 < m2 , õ1 > õ2
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| | | | A notable observation As we can see, laws I, II, II and conclusion I, cited above, are very important conclusions in the research on the spherical shell problem, Fig. 1. Laws É, ÉÉ, ÉÉÉ apply for every moment t1 (t1 > t0 = 0) of the free fall of masses m1 and m2,
within the field of gravity of mass Ì. Note: Following the above, in basic relations (4) and (4.1), is it plain to see that: In the spherical shell problem, Fig. 1: a. When masses m1 and m2 are m1 < m2, then relations (4) apply and relations (4.1) are rejected. In this case, in relations (4), m1 < m2, õ1 > õ2 and Ê > 0.
b. When masses m1 and m2 are m1 > m2, then relations (4.1) apply and relations (4), are rejected. In this case, in relations (4.1), m1 > m2, õ1 < õ2 and Ê > 0. c. When masses m1 and m2 are m1 = m2, then either relations (4) or relations (4.1)
apply. In this case, in relations (4) or relations (4.1), m1 = m2, õ1 = õ2 and Ê = 0. d. Finally, we need to underline that: We are led to these same laws É, ÉÉ, ÉÉÉ and the same conclusion É if, in basic relations (4) and (4.1) instead of relations (4) that we have used in this project, we use relations (4.1). The method is exactly the same, as applied above
for relations (4).
Conclusion In the spherical shell problem, Fig. 1, when m1 < m2 based on relation (27.4) the velocities õ1 and õ2 result from relations (4), where (in relations (4)) m1 < m2, õ1 > õ2 and Ê > 0. Obviously, for m1 < m2 based on relation (27.4) relations (4.1) are rejected,
because relations (4.1) for Ê > 0, yield:
| | | |  | | | | i.e.: õ1 < õ2 which is in contrast to relation (27.4). SUMMARY II As described above, the reasoning (the steps) that we used to solve the spherical shell problem, Fig. 1, are: É. EQUAL MASSES
Step 1: In accordance with the problem, if the data given is m1 = m2 then õ1≠õ2 can never apply. Proof Therefore, if the data given is m1 = m2, then õ1 = õ2 must always apply, as we have proven, i.e.: 
Step 2: Conversely: In accordance with the problem, if the data given is õ1 = õ2 then m1≠m2 can never apply. Proof Therefore, if the data given is õ1 = õ2 then m1 = m2 must always apply, as we have proven, i.e.:
 Conclusion Therefore, from relations (Á.1) and (Á.2), we have: 
ÉÉ. UNEQUAL MASSES Step 3: Therefore, based on relation (Á.3) it emerges that: 
Step 4: In accordance with the problem and based on relation (Á.4), when m1< m2, then õ1 < õ2 can never apply. Proof Therefore, if the data given is m1< m2, then õ1 > õ2 must always apply, as we have proven, i.e.: 
Step 5: Conversely: In accordance with the problem and based on relation (Á.4), when õ1 > õ2, then m1 > m2 can never apply.
Proof Therefore, if the data given is õ1 > õ2, then m1 < m2 must always apply, as we have proven, i.e.: 
Conclusion Therefore, from relations (Á.5) and (Á.6) we have:

Step 6: Therefore, based on relation (Á.7) it emerges that: 
Proof
Relation (Á.8) can be proven very easily, by the same method we used to prove relation (Á.7), as above. These are, therefore, the (6) steps we used to solve the spherical shell problem, Fig. 1, this very important problem of Physics. A SECOND SOLUTION TO THE SPHERICAL SHELL PROBLEM (An important physics problem, for University Professors, students, etc, who still think that the
Theory of Relativity is correct!!!) An interesting, second solution to the spherical shell problem, Fig. 1, is the following: Given the masses m1, m2, Ì (m1 < m2) and the distance h work out the three functions: | | |  | | | | which give us functions of the time t, the velocities õ1, õ2, V, the masses m1, m2
, Ì in terms of the inertial reference system S, Fig. 1. Note: We assume that ratio k, i.e.: | | | |  | |
 |  | | åis relatively small. This second solution, i.e. working out the functions
(27.1), is a very interesting solution to the spherical shell problem, Fig. 1. Obviously, this second solution must be in agreement with law III, as above, and is also proof of this law. Problem Free fall of the Moon to Earth According to Newtonian Mechanics: Let us assume that the Earth and the Moon revolve around their axis and around the Sun and are motionless as per an inertial reference system S.
Let us also assume, Fig. 1, that the Moon has the form of a spherical shell with mass and radius Ro. At the centre of the Moon (i.e. the spherical shell m1) we place an aluminium sphere with mass m2 (similar to the size of a football). We now allow the Moon m1 and the aluminium sphere m2 to fall freely from a distance h, within the field of gravity of the Earth M (where h is the distance between
the Earth and the Moon), Fig. 1. (see, fig. a).  |
We are looking for: 1. After how much time t1 (from the beginning to = 0 of the free fall of masses and , within the field of
gravity of the Earth Ì) will the distance ho (between the centre c΄ of the Moon and c the Earth Ì) be ; 2. At that moment t1, what is the value of velocities , , V masses , , and Ì in terms of the inertial reference system S? Given: The mass of the Moon,
m1= 7,347.1022 kg The mass of the aluminium sphere, m2 = 10 kg The mass of the Earth, M = 5,973.1024 kg The distance between Earth and Moon, h = 384.000 km The radius of the Moon, Ro = 1.738 km Question Which Physics Professor, student, etc, will give us the correct answer to this very important Physics problem? A notable observation Based on the first and second solution to the spherical shell problem described above, it is now proven, clearly and beyond any doubt, that: a. Gravitational fields never have the remarkable property of imparting all bodies (regardless of their
mass) with the same acceleration, as Einstein mistakenly claims, according to the “equivalence principle”. b. The «equivalence principle» (Strong and weak) is a totally false theory of Physics, as demonstrated at http://www.tsolkas.gr/forums/tga5.jpg, http://www.tsolkas.gr/forums/tga4.jpg and http://www.tsolkas.gr/forums/tga6.jpg , mentioned above.
FREE FALL OF UNEQUAL MASSES 1. The momentum of masses m1 and m2 Based on relations (4) and in accordance with law III as above, we have proven that: In the spherical shell problem, Fig. 1, the smaller mass m1, (m1 < m2) falls with higher velocity õ1 (compared to the larger mass m2), which falls with lower velocity õ2, (
õ1>õ2), within the field of gravity of mass Ì. In other words, during the free fall of the unequal masses m1 and m2, (m1< m2) the velocity õ1 of mass m1 is always higher than the velocity õ2 of mass m1, (õ1> õ2). Conversely, with the momentum J1=m1 õ1 of mass m1
and J2=m2 õ2 of mass m2 that is not the case. Specifically, with regard to momentums, J1 and J2, the following happens: From the beginning t0 = 0 of the free fall of the unequal masses m1 and m2, (m1 < m2), until a moment tp, (tp > t0 = 0) the momentum J1
is lesser that the momentum J2, i.e.: |
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | |  | | | | At the moment tp momentums J1 and J2 are equal, i.e.: | | | |  | | | | After the moment tp momentum J1
is always greater than momentum J2, i.e.: | | |  | | |
| Note: The fact that, in relation (28) m1õ1 < m2õ2 and not, e.g. m1õ1 > m2õ2, (see, in detail at the beginning of the link “Galileo and Einstein are wrong” at the site, www.tsolkas.gr.) Therefore, the formulation of the
various relations, which result from the above cases (a), (b), (c) is as follows: 1. In accordance with relation (28):
| | | |  | |
| | and since, in accordance with law III: | | | |  | | | | relations (31) and (32) yield: | | | |  | | | | Obviously, relation (33) is valid from the beginning t0 = 0 of the free fall of masses m1 and m2, (m1< m2) until the moment tp.
- 2. In accordance with relation (29):
| | | |  | | | |
and since, in accordance with law III: | | | |  | | | | relations (34) and (35) yield: | | |  | |
 |  | | Obviously, relation (36) is valid only at the moment tp.
3. In accordance with relation (30): |
 |  |  |
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | |  | | | | and since, in accordance with law III: | | |
 | | | | relations (37) and (38) yield: | | |  | | | | Obviously, relation (39) is valid after the moment tp. The moment tp
will be known as the moment tp of equal momentum. Relations (33), (36), (39), will henceforth be known as basic relations of momentum of the spherical shell problem for unequal masses m1 and m2, (m1< m2). In particular, relation (33) will be known as the first constant relation of unequal momentum and relation (39) will be known as the second constant relation of unequal momentum. In contrast,
relation (36) will be known as momentary relation of equal momentum. In the spherical shell problem Fig.1, we also observe that the motion of the unequal masses m1 and m2, (m1< m2) during their free fall within the field of gravity of mass M is obviously accelerated and, specifically, non-uniformly accelerated, in accordance with relations (4). Finally, since throughout the free fall the velocity õ1 of the smaller mass m1,
(m1< m2) is always higher than the velocity õ2 of the larger mass m2, this means that: In Fig. 2, the velocity õ1 of mass m1, corresponds to curve (õ΄1) and the velocity õ2 of mass m2, corresponds to curve (õ΄2). | | | |  | | | | Fig. 2
When, during the free fall of masses m1 and m2, (m1< m2) within the field of gravity of mass Ì, it occurs, at a moment tp, that the ratio of velocities is equal to the ratio of masses , Fig. 2 in accordance with case (b) of relation (29), the momentums J1=m1õ1 of mass m1 and J2=m2õ2 of mass m2 will be equal J1= J2, (m1õ1=m2õ2) and the momentary relation (36 will apply. Obviously, before the moment tp
the first constant relation (33) will apply, and after the moment tp the second constant relation (39) will apply. It is plain to see that everything we discussed above and which is illustrated in Fig. 2 is a very interesting conclusion of the spherical shell. 2. The kinetic energy of masses m1 and m2 In the same way that we approached the momentums J1 and J2 of unequal masses m1
and m2, (m1 < m2), we will now approach the kinetic energies Ê1 and Ê2 of those masses. Thus, the kinetic energy Ê1 of mass m1, will be: | | |  | | | | and the kinetic energy Ê2 of mass m2, is: | | | |  | | | | In the spherical shell problem, Fig. 1, during the free fall of the unequal masses m1 and m2
, (m1 < m2) at a moment tk, Fig. 3.
| | |  | | |
| Fig. 3 the kinetic energy Ê1 of mass m1 will be equal to the kinetic energy Ê2 of mass m2, i.e.: | | |
 | | | | and since, in accordance with law III: | | |
 | | | | Relations (42) and (43) yield: | | | |  | |
 |  | | Relation (44) will be known as the momentary relation of equal kinetic energies of masses m1 and m2. In addition, the moment tk will be known as moment tk of equal kinetic energies of masses m1 and m2. 2. The time period, Fig. 3, from the beginning t0 = 0 of the free fall of masses m1 and m2 until the moment tk will be: |
 |  | | Relations (48) and (49) yield: |
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Relation (50) will be known as the second constant relation of unequal kinetic energies of masses m1 and m2. Everything that we discussed above is illustrated in Fig. 3. NOTE: We need to stress, at this point, that in the spherical shell problem, Fig. 1, the moment tp in general of equal momentums, Fig. 2, does not coincide with the moment tk
of equal kinetic energies of masses m1 and m2, Fig. 3. Following what we discussed above, a (difficult) problems arises: PROBLEM In the spherical shell problem, Fig. 1, what are the minimum masses m1, m2, Ì and the minimum height h from which the two unequal masses m1 and m2, (m1 < m2) can fall freely
within the field of gravity of mass Ì, so that we have a moment tp of equal momentums and a moment tk of equal kinetic energies? Example From what we discussed above, we observe that in free fall lighter bodies fall with higher velocity than heavier bodies, within the field of gravity of a mass Ì. Thus, if (e.g. in a void) we simultaneously release from a height h over the surface of
the Earth a feather and a tank, and allow them to fall freely, then the feather will reach the surface of the Earth before the tank!!! Conversely (as is well known), Galileo, Newton, Einstein and many contemporary Physicists claim that the feather and the tank will reach the surface of the Earth at the same time. However, what these Physicists claim is obviously a very big mistake, as proven by the solution of the spherical shell problem, as above. SPECIAL CASE WHEN m1 , m2 , << Ì, (m1 < m2 ) In the spherical shell problem, let us now examine the special case where mass m1 of the spherical shell and the point mass m2, are much smaller compared to mass Ì, Fig. 1, i.e.: |
 | | |  |
 |  | | In this based, based on the second of relations (3), we have: |
 |  | | or |
| |
 |  | | Therefore, relation (53) based on relations (51), yields: |
 |  | | In other words, in our case, based on relation (54) mass Ì, is considered, by close approximation, motionless, i.e. it¢s velocity V is: V = 0 in terms of the inertial reference system S, Fig. 1. Let us assume now, Fig. 4, that we let (to = 0) the spherical shell m1
and the point mass m2 (which is at the centre of the spherical shell m1) fall freely and together (simultaneously) from a height h within the field of gravity of the motionless (V = 0) mass Ì. |
 |  | | Fig. 4 Let us also assume that, at the moment t1 > 0 (of the free fall of masses m1 and m2), in terms of the inertial reference system S, we have: 1. Vcm = the velocity of the centre of mass of masses m1 and m2
õ1 = the velocity of mass m1 õ2 = the velocity of mass m2 2. h΄c = the distance of the centre of mass of masses m1 and m2 from the upper limit of height h. h΄1 = the distance of mass m1 h΄2 = the distance of mass m2
|
 |  | | where:
|
| |
 |  | | If we now apply the principle of conservation of energy at the moment t1 > 0
of the free fall, we have: |
 |  | | Relation (56) yields: |
 |  |  |
 |  |  |  |  |  |  |  |  |  |  |  |  |  | |
 | | | | As we can see, in relation (57) the velocity Vcm of the centre of mass of masses m1 and m2
, is independent of masses m1 and m2, i.e. valid for all values of masses m1 and m2. b. Similarly, for mass m1, we have: | | |  | | | | Relation (58) yields: | | | |
 | | | | As we can see, in relation (59) the velocity õ1 of mass m1 at the moment t1 > 0 of its free fall, is independent of mass m1
, i.e. valid for all values of mass m1. c. Similarly, for mass m2, we have: | | | |  | | | | Relation (60) yields: | | | |  | | | | As we can see, in relation (61) the velocity õ2 of mass m2 at the moment t1 > 0 of its free fall, is independent of mass m2, i.e. valid for all values of mass m2
. Note: In cases (a), (b), (c) above, we assume that at the moment t1 > 0, the point mass m2 is always within the spherical shell m1. Also, as we know, the velocity Vcm of the centre of mass of masses m1 and m2 at the moment t1 > 0 is: | | |  | | | | Relation (62) yields: | |
|  | | | | Substituting now in relation (63) Vcm
, õ1, õ2 that result from relations (57), (59), (61) we have: | |
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