Dimensional analysis Definition and 262 Threads

Homework Statement it is likely that the cross-sectional design of a new bridge will give arise to a vortex shedding from its downwind side. Such behaviour can creat harmful periodic forses on the bridge structure, the bridge designers is keen to determine the frequency of shedding. He...

[b]1. Homework Statement [ Average speed of helium at 25C is 1255m/s. Convert this speed to mph Homework Equations The Attempt at a Solution umm i tried to use this: 1255m/s (1mph/.477 m/s) thats all i have and i don;t know if I did this correct

hi guys. i have the london penetration depth defined as \lambda_l = \sqrt{\frac{m^{**}}{4\pi n_{s} e^{2}}}. i'm trying to figure out the dimensionality of it...surely it must be a length, but i get [(Kg)(m^{3})(A^{-1}s^{-1})]^{0.5} in SI units. am i doing something wrong? cheers.

Homework Statement A clock is placed on a floor covered with lead density \rho and thickness d. Use dimensional analysis to show that increase in gravitational field strength at the clock dueo to the layer of lead is proportional to Gd\rhoHomework Equations The Attempt at a Solution to show...

Homework Statement From Wave theory it is found that the only properties of the wave and the medium that the wave travels across that may determine the speed of propagation of the wave v are the density ρ of the fluid the wave travels across, the wavelength λ of the wave, and the surface...

Homework Statement hi I am trying out a question on dimensional analysis , I am having trouble finding the solution when the force is non linear , the situation is a mass resting on a smooth surface attatched to a spring , the spring is attached to a wall on its other end , Homework...

Homework Statement The dimensions for all sorts of energy must be equal. Then the following should hold: By E=Fs and E=VIt, [Fs] = [VIt] [M][L]2[T]-2=[V][Q] Now, according to some online lectures I watched some time ago, the dimensions of time, length, and mass are the three...

Homework Statement I am doing a project to build a scaled wave tank. "This project involves the design, construction and testing of a wave tank. When studying the hydrodynamics of a scale model or prototype, it is important to choose an appropriate scale. To determine tank and wave dimensions...

Homework Statement The velocity,v of the sound in a gas depends on the density, p and the pressure, p of the gas. By using dimensional analysis, find a possible relation between v, p and p. Homework Equations [v] = LT-1 [p] = ML-3 [p] = ML-1T-2 The Attempt at a Solution well i...

Homework Statement The Attempt at a Solution I'm really new to this, and the professor didn't explain it well. IDK if I did that right so far, but I'm not sure what to do next. What does it mean by the units of .00256? Thanks

Homework Statement where F is the magnitude of the gravitational attraction on either body, m_1 and m_2 are the masses of the bodies, r is the distance between them, and G is the gravitational constant. In SI units, the units or force are kg* m/s^2, the units of mass are kg, and the units of...

Which one of the quantities below has dimensions equal to ML/T2 a) mv b) mv2 c) mv2/r d) mrv e) mrv2/r2 I tried splitting it up in M*(L/T)*1/T which would lead me to mv*T-1 and then I get stuck Please help!

Homework Statement Use dimensional analysis to find a formula for the free-fall time τ of an astrophysical ball of gas. In this system, the only force is gravity, therefore the only quantities are Newton’s constant, G, and the mass and the radius of the sphere, M and R respectively...

Homework Statement I have a few problems that I'm unsure how to proceed with... 1. Ethylene glycol, and antifreeze, has a density of 1.1 g/cm^3. What is the mass, in grams, of 417 mL of this liquid? 1 cm^3 = 1 mL 2. To determine the density of a liquid, a flask is weighed empty (108.6g)...

Homework Statement For about 10 years after the French Revolution, the French government attempted to base measures of time on multiples of ten: One week consisted of 10 days, one day consisted of 10 hours, one hour consisted of 100 minutes, and one minute consisted of 100 seconds. What are...

1. Homework Statement : Use dimensional analysis to determine how the linear speed (v in m/s) of a particle traveling in a circle depends on some, or all, of the following properties: r is the radius of the circle; ω is an angular frequency in s-1 with which the particle orbits about the...

From dimensional analysis, the speed of water waves can be determined as follows: Only the gravitational constant 'g=10 m/s^2' matters. g has units of L/T^2, so the only way to get a velocity is \frac{1}{(2\pi)^{\frac{1}{2}}}g^{\frac{1}{2}}*\lambda^{\frac{1}{2}} where \lambda is the...

given a distance s = 8.6m, time t = 2s, and a mass = 1.01kg, evaulate the expression to a physically appropriate accuracy? m3 = 1.013 = 3.03kg is this correct

are these dimensional analysis questions correct A = area V = volume v = speed p = density 1. VA / v = L3 L2 L-1 T-1 = L4T-1 2. V2/3 A = (LT-1)2/3 L2 = L2/3 T-2/3 x L2 = L10/3T-2/3 3. 3A3 + 2V2 = A3 = L6 V2 = (L/T)2 = L2T-2 = L4T-2 are these correct

What's the problem with using dimensional analysis to derive the Lorentz transformations?

Homework Statement Hi. I have a function that contains 4 variables: Q, R, \mu, dp/dx I wish to choose 3 of them, such that they cannot be combined into a dimensionless product.I have chosen (correctly) R, \mu, dp/dx and I would like to know if my method sounds correct: If we know the...

Hi guys, have been reading these forums for a very long time, have always found it very helpful and informative. There's this problem which I can't seem to get my head around, it seems very straight forward, but every time I try to do it, I always end up doing it wrong. I would greatly...

V(t)=IR(1-e^{t/RC}) \rightarrow ln|IR - V(t)| = ln|IR|-t/RC The first equation below has units of voltage. the logarithm has units of voltage, but what does ln|IR| and ln|V| physically mean? The purpose of this question is that if you plot the natural logarithm of the...

Homework Statement The first equation below has units of voltage. Homework Equations V(t)=IR(1-e^{t/RC}) \rightarrow ln|IR - V(t)| = ln|IR|-t/RC The Attempt at a Solution the logarithm has units of voltage, but what does ln|IR| and ln|V| physically mean?

Homework Statement The ideal gas law can be recast in terms of the density of a gas. a) Use dimensional analysis to find an expression for the density \rho of a gas in terms of the number of moles n, the volume V, and the molecular weight M in kilograms per mole. b) With the expression...

Just read this, and got a bit confused when trying to do it...Homework Statement We have a diffusion equation situation with a semi-infinite rod, so: \frac{\partial \theta}{\partial t} = \lambda \frac{\partial^2 \theta }{\partial x^2 } at infinity the rod is at some fixed temperature...

Homework Statement The question states which of the following equations are dimensionally correct? (a) v^2=v^2+2at or (b) v^2=v^2+2ax Homework Equations v=[L]/[T], x=[L], a=[L]/[T]^2 The Attempt at a Solution (a) v^2=v^2+2at [L]^2/[T]^2=[L]^2/[T]^2+([L]/[T]^2)([T])...

I have been reading a paper which introduced classical mechanics concerning only one dimension. Before we get into anything about displacement and velocity, I read about dimensional analysis. There is a section of the paper which isn't very well explained and I hope someone can explain it to...

This is an elusive subject with added order of magnitude. If that doesn't make sense, well... It tells that I'm confused. Say rate of fluid flow in a uniform cross-sectional area pipe |A|=L^2,|R|=L^3*T^-1. Is it customary that I get all variebles to the same order of magnitude and be...

Homework Statement 1. Use the method of Dimensional Analysis to show that the unknown exponents in Equation (1) are l=-1/2, m=-1, and n=1/2. Homework Equations Equation (1) is \lambda = k \mu ^{l} f ^{m} T^{n} Where: \lambda is the wavelength; f is the frequency of the sound; T is...

Homework Statement determin the dimensions of \alpha in the following a)Sin(\alphaX^{}2) (alpha* X squared) (X is a distance) b)10\alphat3 c)cot(\alphaX2/R) (R is a radius) d)e(hf/\alphaT - 1 (h is Plancks constant with units J*s) ( f is frequencyHomework Equations The Attempt at a Solution...

Hello everybody, I am taking a basic undergrad General Chemistry I course and am just having a little trouble brushing myself up on dimensional analysis (or factor label). This is the problem. The area of a telescope lens is 7903 mm2. (a) What is the area in square feet? (b) If it takes a...

Homework Statement Problem #1 http://img230.imageshack.us/img230/705/hwpicvf5.jpg Problem #2 http://img149.imageshack.us/img149/3196/hwpic2fb4.jpg Homework Equations The Attempt at a Solution Problem #1) I do not know where to proceed from here I have. T = 2pi * square...

Hi, I haven't looked at math/physics in awhile and want to make sure I did this correctly lol Homework Statement The viscosity of a gas depends on the mass(m), the effective diamtere(d) of the gas and the mean speed(v) of the gas molecules. The unit of viscosity is (pascal * second). use...

Homework Statement Basically, I have a constant that is 1/mass. I need to find out how to relate this to my function which has units eV/A^2 to have results in THz^2.Homework Equations The Attempt at a Solution I think I would just have the mass in units of MeV/c^2 and then convert c^2 into...

any body know... question: true or false?? dimensional analysis can give you the numerical value of constants of propotionality that may appear in a algebra system... and can u give the reason too...??

Homework Statement If .060 faraday is passed through an electrolytic cell containing a solution of In +3 ions,what is the maximum number of moles on In that could be deposited at the cathode? Show half cell equation and demensional analysis. Homework Equations N/A The Attempt at a...

Hullo was wondering if anyone could help me. In dimensional analysis using then buckingham pi theorum, I'm not sure how to express an angular velocity in terms of basic dimensions (i.e M (mass), L (length), T(time), \Theta (temp). I know an angular velocity is revs/s or rad/s so its going to...

Homework Statement Hi Im having some difficulty with the following question: Figure P1.14 shows a frustrum of a cone. Of the following mensuration (geometrical) expressions, which describes (a) the total circumference of the flat circular faces, (b) the volume, and (c) the area of the...

img512.imageshack.us/img512/2985/42904009cw1.jpg Hey guys, I am a bit stuck on this prolbem. When it says identify the characteristic physical scales is this referring only to the length scales (l, h, b)? or is U, gravity, density and viscosity included as well? Now the only two...

Hi everyone. Can someone recommend a book that covers dimensional analysis/scaling with Differential Equations? All the books I've looked at on DEs have very little on dimensional analysis/scaling. For instance, I set up a DE for vertical projectile motion with air resistance, I want to use...

I am not to sure how to calculate this out A rectangular plate has a length of 23.2 +/- .2 cm and a width of 9.0 +/- .1 cm. calculate the area and its uncertainty Anyhelp would be greatly apriciated

I am having trouble with one of the problems on my hw. The question is: Because light carries momentum, it creates pressure when it shines on something. This has led people to propse using "solar sails" instead of conventional rocket engines on interplanetary or interstellar space craft. A...

I understand the concept of dimensional analysis and what it's used for etc..My question refers to a dimensionally correct or incorrect equation being true or false. Here are the possiblities: 1. A dimensionally correct equation may be correct. 2. A dimensionally incorrect equation may be...

1. A simple pendulum consists of a light inextensible string AB with length L, with the end A fixed, and a perticle of mass M attatched to B. The pendulum oscillates with period T. It is suggested that T is proportional to the product of powers of M, L and g. Use dimensional analysis to find...

y = (2m) cos (kx), where k = 2 m^-1 it says that the equation is dimensionally correct but i don't understand why...

Dimensional Analysis And Projectile Motion Problem 1. The work I have shown below is my attempts at doing the steps shown to get that equation in the problem, which is what the "answer" is. I need to find the work. Am I on target? And I am totally clueless as to how I get the second...

I have this queston: The flow rate in a pipe is assessed by measuring the speed of rotation of a propeller having its axis along the pipe centre-line. Show by dimensional analysis that the volume flow rate, Q, is given bu the expression: Q=(D^3).N.Phi.(d/D,(density.(D^2).N)/viscosity)...

What can "Dimensional Analysis Techniques & Buckingham Pi Theory" be used for? GS

Homework Statement The speed, v, of an object is given by the equation v=At^3 - Bt, where t refers to time. What are the dimensions of A and B? Homework Equations None, but I know that to find dimensions, we look at the units that make up the variable, like the area of a room is [L^2]. I...