Confusion on wording of a dimension problem

AI Thread Summary
The discussion centers on expressing the speed of sound waves in a gas in terms of pressure and density, represented by the equation v=ap^bq^c. The dimensions of pressure are clarified as m/((LT)^2), while the dimensions of density are confirmed to be m/L^3. Participants suggest using parentheses in the equation for clarity and recommend applying the Buckingham Pi Theorem to solve for the dimensionless constants b and c. The conversation emphasizes the importance of correctly identifying units for each term to resolve the confusion. Understanding these dimensions is crucial for accurately determining the values of b and c in the equation.
camillevoll
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the speed v of sound waves in a gas can be express in terms of the pressure p and the density q (mass per unit volume) of the gas, as v=ap^bq^c, where a, b, and c are dimensionless constants. The dimensions of pressure are m/((LT)^2). What must be the values of b and c.

I am confused on what to write for the dimensions of q. Would it be m/L^3 as in mass/volume?
 
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camillevoll said:
the speed v of sound waves in a gas can be express in terms of the pressure p and the density q (mass per unit volume) of the gas, as v=ap^bq^c, where a, b, and c are dimensionless constants. The dimensions of pressure are m/((LT)^2). What must be the values of b and c.

I am confused on what to write for the dimensions of q. Would it be m/L^3 as in mass/volume?

Welcome to the PF.

Could you add some parenthesis to your equation to eliminate the ambiguities?

"v=ap^bq^c"
 
v=a(p^b)(q^c)
 
camillevoll said:
v=a(p^b)(q^c)

Ah, that helps. Now can you fill in the units for each term? I usually use square brackets to indicate the units like v[m/s].
 
v=[L/T], p=[M]/[L][T^2]
 
Read up on the Buckingham Pi Theorem. That is what is involved here.

Chet
 
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