Originally Posted by oz93666 When I was taught physics many decades ago , there was no talk of different kinds of mass ... I was taught there is ONE mass , measured in Kg ...and it is the property which resists acceleration , and causes gravity .... 
Whoever taught you that was wrong.
Originally Posted by oz93666 If Mr Ohanian is suggesting there are now two kinds of mass he needs to offer experiments which can prove this hypothesis showing gravitational and inertial mass are not the same ...otherwise it's just talk ... marks on blackboard ... unproven theory. 
In the first place nobody ever said that it was Ohanian's theory. I said he is an example of one who defines it in this texts. But it'd be difficult to find a decent text which doesn't define gravitational mass. When I started college in the early 80's the text everyone was using for basic physics was
The Fundamentals of Physics by Halliday and Resnick
Nowadays one uses a text like
Physics For Scientists and Engineers by Knight
If you search online you might be able to find a place to download a copy of them to read for yourself. Try this to start
https://archive.org/details/Fundamen...yResnickWalker
Each of these texts defines the term "gravitational mass." In any case its all been tested experimentally to high degrees of accuracy.
I wrote an entire paper on the concept of relativistic mass which includes all three kinds of mass. See:
https://arxiv.org/abs/0709.0687
In this paper I describe these concepts and their origins. But the definitive books on the subject were written by Max Jammer. They are
Concepts of Mass in Classical and Modern Physics
which you can download and read at
Concepts of Mass in Classical and Modern Physicsby Max Jammer  Review by: C. Truesdell  download Concepts of Mass in Contemporary Physics and Philosophy
which you can download and read at
Concepts of mass in contemporary physics and philosophy: Max Jammer; Princeton University Press, Princeton, 2000, xi+180pp., price US $41.50, ISBN 069101017X  Roberto Torretti  download
Each of these define and explain the three concepts of mass as I do in my own paper. They are
inertial mass – Mass which resists changes in momentum
passive gravitational mass – Mass acted upon by gravity
active gravitational mass – Mass that is the source of gravity
You'll find these concepts defined almost everywhere in physics. For example, see
https://en.wikipedia.org/wiki/Mass
Inertial mass measures an object's resistance to being accelerated by a force (represented by the relationship F = ma).
Active gravitational mass measures the gravitational force exerted by an object.
Passive gravitational mass measures the gravitational force exerted on an object in a known gravitational field.

The important thing to understand here are the
different physical concepts of mass. One can
choose the gravitational constant in such a way that they all have the same numerical value.
Originally Posted by oz93666 If Mr Ohanian is suggesting there are now two kinds of mass he needs to offer experiments which can prove this hypothesis showing gravitational and inertial mass are not the same ...otherwise it's just talk ... marks on blackboard ... unproven theory. 
You're thinking like a mathematician now, not like a scientist. First off physics is not about proving anything. If someone every told you that something was proven in physics then they were wrong. Do yourself a favor and watch this video:
http://www.newenglandphysics.org/com...an_Guth_04.mp4
As for marks on a blackboard  Well my friend, you'll just have to learn about these concepts before we go past here. Until you learn about it you won't understand what's wrong with that statement. Read Max Jammers books and you'll understand the physics. I'll give you a preview
Newton's Law of Motion: F = dp/dt where p = m[sub]i[/sub]v
where m[sub]i[/sub] is defined as the inertial mass of the particle
Newton's Law of Gravitation: F = HMm/r[sup]2[/sup]
where H is a constant of proportionality
M is the source of gravity
M acts on m
M is defined as the active gravitational mass
m is defined as the passive gravitational mass
Einstein's Principle of Equivlenence states
m is proportional to m[sub]i[/sub], i.e. m = k*m[sub]i[/sub]
Therefore
F = HMm/r[sup]2[/sup] = HM(k*m[sub]i[/sub] )/r[sup]2[/sup]
F = GMm[sub]i[/sub] )/r[sup]2[/sup]
G is defined as the
gravitational constant
This is all standard stuff defined in all college level basic physics textbooks. Have you ever read one? Most don't differentiate between active and passive gravitational mass. In fact Ohanian asserts that it doesn't make sense to do so. I disagree.
Hint:
Before any experiment can be done one must first
define the quantities that are being measured. Only after that can a measurement be made.
For a journal articles on active gravitational mass see
Active Gravitational Mass by Charles W. Misner and Peter Putnam
Phys. Rev. 116, 1045 – Published 15 November 1959
https://journals.aps.org/pr/abstract...ysRev.116.1045
A very famous paper on the concept see Negative mass
Negative Mass in General Relativity by Herman Bondi, Rev. Mod. Phys. 29 (3): 423–428.
You can download and read this article at
Negative mass in general relativity  W. B. Bonnor  download
In this article Bondi talks about the possibilities of these three different masses having different signs and the theoretical concepts which follow.
You can't look for those things which you choose not to think about and ascribe only to blackboards.
When it comes to tachyons the mass is imaginary. Imagine that?
https://en.wikipedia.org/wiki/Tachyon
Gerald Feinberg proposed that tachyonic particles could be quanta of a quantum field with imaginary mass.

See also:
https://en.wikipedia.org/wiki/Tachyonic_field
Frankly I'm confused as to your objection of a concept which you don't appear to ever even heard of. Why is that?