The review of a new theory of physics requires time to both read and digest the ideas being presented and often this time is not readily available. An author writing about a new theory may therefore find it helpful to adopt an approach that permits other physicists to make a quick assessment of the plausibility of the new theory, rather than initially expecting them to read a lengthy detailed description of the theory.

If the theory appears plausible, and especially if it relates to aspects of their own research work, then physicists are far more likely to find the time required for a more thorough
investigation. Presumably we expect new theories to blend with time so that the development of the *fundamentals of physics* eventually lead to the *unified theory of physics?*

Two key areas that permit a relatively quick and intuitive assessment of a new theory are the summaries of the *Key Expressions* and the *Physical Constants of Nature* resulting
from the new theory presented alongside the current expressions and constants of the corresponding classical values; together with a brief explanation of the associated parameters and key
changes.

*Key Expressions* of the physics involved, usually provides an immediate insight to the differences between the new and classical theories.
For example, with the perspective of *Physics in 5 Dimensions*^{(15) }an object O and observer P are
following two different paths with the common constant velocity c, subtending an angle θ to each other. Object O of mass m is seen by observer P to have a relative velocity vector v4, defined to
be orthogonal to the path of the observer P and shown to be aligned with the x-axis in the figure below. Object O also has a second velocity vector v5 parallel to the y-axis and we note
that for the three velocity vectors (v4, v5, c) associated with object O we have from simple geometry the scalar relationship c^{2 }= v4^{2 }+ v5^{2}. The Physics in 5 Dimensions relativistic Kinetic Energy term of is given by K5=mv4^{2}/(1+v5/c)
and for objects with low velocity, when v4«c and v5≈c, we get K5≈ mv4^{2}/2 = KE; the Newtonian kinetic energy term of
classical physics.

From the perspective of Physics in 5 Dimensions, the mass m does not vary with velocity v4 as with the perspective of classical physics where a rest mass mo is defined when v4=0. We find that the relationship m v5 = mo c links these two perspectives. The velocity vector v5 is not seen in classical physics and so the mass has to vary to compensate for the missing momentum and energy associated
with v5. Using mv5=moc and c^{2 }=
v4^{2 }+ v5^{2} to eliminate v5
we get back to classical physics and the reader can check that this results in Einstein’s relativistic mass formula where m=mo/√(1-v4^{2}/c^{2 }. It follows that the common constant velocity c of *Physics in 5 Dimensions* has to take the value of the speed
of light in order to comply with Einstein’s mass formula.

If the effect of a new theory on the Key Expressions is also linked to changes and/or explanations of the *Physical Constants of natur*e then a feeling for the plausibility of the new
theory may be rapidly established. For example, with the theory *Physics in 5 Dimensions* all particles and objects have an individual fixed value of angular momentum h5 = 2 𝝅 m R4 v4
where an object orbits on radius R4 with a radial velocity v4. The angular momentum h5 is a constant for the body or particle which means that the product R4 v4 is also a constant; so that as v4
gets smaller then R4 gets larger and vice versa.

This expression applies to all particles and bodies in 5-dimensional space and in the special case of an electron orbiting the nucleus of a hydrogen atom we get he =2𝝅 me v4e R4e where he is Planck’s constant and me, v4e and R4e are respectively the mass, orbital velocity and radius of orbit of the electron.

This approach can also demonstrate the extent to which a new theory has been developed by illustrating how the new theory applies across many different fields of physics together with the various
applicable *Key Expressions and Physical Constants of nature*.

Further examples can be found in the paper *Physical Constants & Key Expressions of Physics in 5 Dimensions*^{(16) }. Many constants of nature are clearly defined by the theory and have expressions that permit an accurate calculation of the value of the constant. Relationships linking
different constants of nature are also developed.

*The plausibility of a new theory is based on a quick and intuitive assessment of the key expressions and the physical constants of nature resulting from the new theory presented for
comparison alongside the current classical physics key expressions and physical constants of nature.*

**References:**

(15) Physics in 5 Dimensions, Alan Clark, 2017, 496 pages, Winterwork, Borsdorf, ISBN: 978-3-96014-233-1

(16) Physical Constants & Key Expressions of Physics in 5 Dimensions - An objective view of physics - see: https://www.researchgate.net/publication/284444212_Physical_Constants_Key_Expressions_of_Physics_in_5_Dimensions_-_An_objective_view_of_physics

The Book by **Alan Clark**- **Physics in 5 Dimensions** - is also available as a PDF file to
members of ResearchGate **here**.