Is INERTIA a physical quantity?

Inertia is simply a principle, a concept... Concepts don't have units themselves, but units are applied when you put the concept into practice. For example: the volume of an ideal gas is determined by the number of molecules and air pressure... This is a concept, but if I want to apply this, I can say 1 mole of neon at one atmosphere of pressure has a volume of 22.4 liters (I think... I possibly forgot the real value).. Anyway, inertia simply says objects in motion stay in motion - Newton's first law, which by itself has no units until it is applied to a problem... In this case, inertia may be applied in a variety of ways which could include mass, force, and velocity units ( distance and time)

Hi! Sorry to bother but a while ago I asked a question about the difference of the 2 average speed formulas. You said that the one that the first formula only applies to an object with constant acceleration. Let's say if I have to solve a problem and I need average speed formula to solve. How do I know if I should use the first or second formula because it doesn't say which one is constant or not. Can you please explain it again more better please? Thank you

I think Wikipedia gives a very elegant answer to your question.

Wikipedia gives answer to your question.

Hey asshole thanks for answering my question with a smartass remark. I asked a question obviously i don't know how to find the answer.

CAN YOU PLEASE GO BACK TO MY QUESTION I ADDED MORE DETAILS