Formula conventions and energy question

In summary, The conversation is about the use of formulas in a textbook on natural disasters. The first formula discussed is the velocity of tsunami waves which uses the variables C, D, and g. The person speaking points out that the convention for representing velocity is usually lowercase v and that units are typically not italicized. The second formula is for the period of a pendulum, which uses the variables P and L, and the person speaking suggests that a constant with units of time/distance^2 should be included to make the formula dimensionally consistent. The third formula is for the energy of a moving object, which uses the variables E, m, and C, and the person speaking notes that everything should be italicized and that the formula may
  • #1
tony873004
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** 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.

The velocity of tsunami waves depends on the water depth and gravity:
[tex]{\rm{C}} = \sqrt {g{\rm{D}}}[/tex]
C=sqrt(g D)
where
C = velocity in meters per second
D=depth in meters
g=gravitational acceleration (9.8 m/sec2)

I know the letters used are just man-made convention. I could say
[tex]{\rm{j}} = \sqrt {y{\rm{Z}}}[/tex]
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
[tex]v = \sqrt {gd} [/tex]
v=sqrt(gd)
The next formula in question is:
the period (P) of the pendulum, or total time for a back-and-forth smovement, is equal to the square root of the pendulum length (L):
[tex]P = \sqrt L[/tex]
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
[tex]P \propto \sqrt L [/tex]
P propto L
?

The 3rd formula in question is:
Recall that the energy of a moving object is equal to its mass times the square of its velocity.
[tex]{\rm{E = mC}}^{\rm{2}} [/tex]
E=mC2
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:
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  • #2
I suspect that the authors of that textbook are not physicists. :rolleyes:

[FYI: The Latex problem is being looked into.]
 
  • #3
Doc Al said:
I suspect that the authors of that textbook are not physicists. :rolleyes:
No, they're geologists. Maybe they have their own conventions?
 

1. What are some common formula conventions used in science?

Some common formula conventions used in science include using symbols and subscripts to represent elements and their quantities in a chemical formula, using superscripts to indicate charges in ionic compounds, and using parentheses to show the arrangement of atoms in a molecular formula.

2. How do you calculate energy in a chemical reaction?

The amount of energy involved in a chemical reaction can be calculated using the formula E = mc^2, where E is the energy, m is the mass of the reactants, and c is the speed of light. This formula is based on Einstein's famous equation for the relationship between mass and energy.

3. What is the law of conservation of energy?

The law of conservation of energy states that energy cannot be created or destroyed, but can only be transformed from one form to another. This means that the total amount of energy in a closed system remains constant.

4. How is energy related to chemical bonds?

The breaking and forming of chemical bonds involves the transfer or release of energy. Breaking bonds requires energy, while forming bonds releases energy. This energy is stored in the bonds and can be released during a chemical reaction.

5. How do exothermic and endothermic reactions differ in terms of energy?

Exothermic reactions release energy in the form of heat, while endothermic reactions absorb heat and require an input of energy to occur. This can be seen in the change in temperature of the surrounding environment during a reaction.

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