# Formula conventions and energy question

1. Aug 16, 2008

### tony873004

** edit: did I forget how to use tex, or is there a system bug? I'll type the formulas normally below the tex
I'm reading through a textbook on natural disasters. There are some formulas that don't look right. Let me get some opinions here.

I know the letters used are just man-made convention. I could say
$${\rm{j}} = \sqrt {y{\rm{Z}}}$$
j=sqrt(y/Z)
as long as I define what each variable or constant stands for. But it seems like most literature has adopted a common convention which is not followed here. I've never seen C used to represent velocity, unless its the speed of light, in which case I believe it should be lower case c. Velocity is usually lowercase v. Also, it seems to me that the common convention is that variables and constants are italicized while units are not. So it would seem to me that common convention should give this formula as
$$v = \sqrt {gd}$$
v=sqrt(gd)
The next formula in question is:
P=sqrt(L)
Here they're italicizing their variables, which is what I would expect. But this formula does not seem right. For example, if I plug in 1 meter for length, then my period becomes 1 m1/2. It seems to me that a constant with units of time / distance2 would be needed to make this formula dimentionally consistent. But since they're proportional, wouldn't it make more sense to say
$$P \propto \sqrt L$$
P propto L
?

The 3rd formula in question is:
Again, nothing is italicized. It seems to me that everything here should be italicized. Again, C is used for velocity. Wouldn't it be more correct to say speed since no vector arrows are used. And should this formula have a 1/2 in front of m turning it into the kinetic energy formula? They're not talking about the mass converting into energy, as in Einstein's equation, but the energy of an asteroid striking Earth.

Last edited: Aug 16, 2008
2. Aug 16, 2008

### Staff: Mentor

I suspect that the authors of that textbook are not physicists.

[FYI: The Latex problem is being looked into.]

3. Aug 16, 2008

### tony873004

No, they're geologists. Maybe they have their own conventions?