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
Messages
3
Reaction score
0
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?
 
Physics news on Phys.org
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
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top