# Can constant acceleration/velocity be written as $a_c$/$v_c$? [closed]

I was wondering if constant acceleration, for example, could just be written as $a_c$. I have seen it written that way, but I was not sure if it was legitimate. I did a quick search on Google but to no avail, so I turned to the best website out there.

I am new to physics, so having the knowledge of properly writing functions is a big deal. And if that is how you would denote constant acceleration the would just $a$ for acceleration mean that the acceleration is changing, as in a slope on a graph?

Sorry if this is confusing!

## closed as primarily opinion-based by AccidentalFourierTransform, Kyle Kanos, Bill N, Jon Custer, sammy gerbilMar 2 '17 at 0:34

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• You can write it anyway you want. There is not law of physics notation. The important question is "Will this be understood?" and the answer in this case is "You'd better say what you mean by that." – dmckee Mar 1 '17 at 16:34

As dmckee says in a comment there is no hard and fast rule for writing a constant acceleration or velocity, so it's up to you to make clear what notation you are using.

Having said that, if I saw $a_c$ I would not interpret this as meaning the acceleration is constant. When I see the notation $a_i$ I normally expect this to mean the components of the acceleration vector ($a_x$, $a_y$, $a_z$) or with multiple bodies the acceleration of the $i$th body. I've never seen a $c$ subscript used to mean that quantity is constant.

To the extent that there is an accepted convention constants are generally written using uppercase letters, so if I wanted to say the acceleration was constant I would use:

$$a = A$$

and explain in the text the meaning of the constant $A$. Likewise for velocity, though since $V$ is sometimes used as the symbol for potential energy you'd need to make it clear in the text what you meant.

• $a_c$ sometimes means centripetal acceleration. – AccidentalFourierTransform Mar 1 '17 at 16:47
• @AccidentalFourierTransform: Yes, although that is of course a component of a vector as I mentioned :-) – John Rennie Mar 1 '17 at 16:49
• Great information! I appreciate your help :-) – Carlos Carlsen Mar 1 '17 at 16:50
• @JohnRennie I know, that's why I mentioned - because it was a concrete example of what you said. – AccidentalFourierTransform Mar 1 '17 at 16:50