I read, some time ago about a dimensionless constant in physics [closed]

and, my terminology is probably off, but, I think I can explain with an example.

Take a Newton, which can be described as a KG*Meter/Second^2 - which frankly, written that way, looks confusing to me, and it makes more sense written in English "it's a force that will accelerate a 1 KG object 1 meter per second per second." - assuming no friction or angular momentum of-course.

Now, here's my question. I read once that there was a physics formula that was purely numerical and didn't have an units (units being, "KG" "Meter" and "Second", etc) - and I remember reading that once, but I've been googling and I can't find it.

Does that ring a bell, that physics formula where the units cancel out and you're just left with a number?

And my 2nd question is, is that relevant to anything or is it just a mathematical quirk?

I don't know if that makes sense and if doesn't, I'm going from remembering something I came across years ago and I might not have it exactly right in my memory.

closed as unclear what you're asking by John Rennie, ACuriousMind♦, Kyle Kanos, Martin, JamalSFeb 19 '15 at 14:59

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• There are lots of dimensionless constants used in physics. I think the best we can do is point towards the list I've linked so you can look through for the particular constant you remember. – John Rennie Feb 19 '15 at 10:51
• There's also non-dimensionalization which is where you divide your equation by a characteristic scale and obtain an equation that has no dimension. – Kyle Kanos Feb 19 '15 at 14:01
• As a sidebar, I found what I was looking for. I was posting from memory, not knowing what it was called, which is why my question seems vague. This is what I was asking about: en.wikipedia.org/wiki/Fine-structure_constant – userLTK Nov 6 '18 at 7:04