Wavelength with P/Q exponent equation-solve for P/Q

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Homework Help Overview

The discussion revolves around the relationship between the speed of ocean waves, wavelength, and gravitational field strength, as described by the equation V = Kλ^P g^Q. Participants are tasked with finding the values of the exponents P and Q through dimensional analysis.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of dimensional analysis to isolate and solve for the exponents P and Q. There are differing opinions on whether to apply logarithmic transformations to the equation, with some questioning the validity of this approach.

Discussion Status

The discussion is ongoing, with participants exploring different methods to approach the problem. Some have suggested taking logarithms to simplify the equation, while others express uncertainty about this method based on prior guidance from a professor. Clarification on the exact problem statement has also been sought.

Contextual Notes

There is mention of a dimensionless constant K, and the problem is framed in the context of dimensional analysis without numerical values provided. Participants are navigating the implications of their assumptions regarding the equation's structure.

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Homework Statement


Speed of an ocean wave depends on the wavelength [tex]\lambda[/tex] in meters and
gravitational field. (see equation below). Find values of P and Q. K is a constant and has no dimensions


Homework Equations



V = K[tex]\lambda[/tex]PgQ

The Attempt at a Solution



V=velocity, which is m/s
and i can disregard K because it is a constant which has no dimensions.
g = m/s2
[tex]\lambda[/tex] = m
plugging in the numbers; i get:

m/s = mP(m/s2)Q

here is where i get lost. i don't know how to bring the exponents down so i can solve for it
 
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You have V = K LPgQ
(I used L in place of lambda.)
So LP = V/[K gQ]

To solve for P, take the log of both sides, then divide both sides by log L.

To solve for the other exponent Q, first solve for gQ in a way similar to how I solved for LP, then take the log of both sides, and divide both sides by log g.
 
are you sure? i was workin on this with my prof and he told me not to take the log; that's what i thought of doing initially
and i have no numerical values for the equations; its all dimension analysis
 
OK, what's the exact statement of the problem? As you have it in post 1, it appears that you need to solve for P and Q.
 
The speed of ocean waves depend on their wavelength [tex]\Lambda[/tex] (measured in meters) and the gravitational field strength g (measured in m/s^2) in this way:

v = [tex]\Lambda[/tex]PgQ

where K is a dimensionless constant. Find the values of the exponents P and Q
 

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