Units Definition and 976 Threads

Homework Statement I need to convert a value in cm^3s^-1 to litres per second. I know that 1 litre=10^-3m^3 Homework Equations The Attempt at a Solution Could someone please help?

Having much difficulty with the problem below. Any direction would be greatly appreciated. A waste gas stream contains .045 mole of ammonia per mole of carrier gas. Its desired to design an absorber using water which will reduce the ammonia concentration in the exit gas from the absorber to a...

Homework Statement I have a lab report due next week and I'm almost done with it. However I'm totally stuck on the last part where it is wrote in a description of the experience : c=\frac{(m+M_e)(T_f'-T'_i)}{m(T_c-T_f)} where c is the specific heat of a metal. If I work out the units in the...

Homework Statement A Consistency question regarding the dimensions of the KG Equation. Homework Equations M^2=\frac{\hbar c}{G} for a quantization of gravitational charge on matter The Attempt at a Solution I know a few things however concerning the KG equation. It is directly...

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?

Dear Physics Gurus, o:) I am trying very hard to understanding the units used to measure torque. I know there is a unit called kilogram force centimeter, and 1 ounce force inch = 0.072007790632 kg force cm. My problem is I do not understand what these units mean. I could only find...

Geometrized units use the multiplication factor to convert for example mass to length, in this case the factor would is G/C^2. I know this is to do with setting c=G=1. How does one derive the multiplication factor from this? Any help greatly appreciated. Shane

Does the gravitomagnetic B-field (from the GEM equations) have units of frequency (1/s)? And if so, what exactly does the B field describe? I guess what I'm really trying to find out is whether the B field around say a rotating spherical object describes the rate of frame dragging, or does...

Homework Statement ok this might be a stupid question but I am working on a problem with springs and velocity and whatnot. anyways the units are american, 5lb, k=2lb/in, the diagram is dimensioned in inches. do i have to convert all them to N,kg,and meters. Homework Equations...

It really annoys me when professionals mess up unit conversions. From http://news.yahoo.com/s/afp/20090403/sc_afp/usclimatewarming_20090403144320 (1 million km^2 is actually 390,000 square miles.)

Homework Statement In a problem to determine the maximum elastic potential energy of a molecule, I have the following equation: A= \sqrt{\frac{6.626*10^-34 Js}{2\pi}}\times(\frac{1}{(1.14*10^-26kg)(1.85*10^3N/m})^(1/4) Homework Equations The Attempt at a Solution The answer is...

Hello! I was wondering if someone could help me with a problem of units! I'm currently deriving probability equations for neutrino oscillations and I'm stuck with units! I have: [(mass)^2 * time]/[4*energy] and I want to write it as [1.27 * (mass)^2 * distance]/[Energy] with distance in...

Im am trying to figureout how to calculate savings using a VFD - Variable Frequincy(Speed) Drive Direct energy savings easy I am trying to Calculate the savings in AIR FLOW/+/Air temp-differerance Not exausting 75'F air outside at say 10,000 CFM - And not bringing in 30'F Air in the...

This is perhaps a stupid question but: When we use natural units and set h=c=1, do we choose appropriate units so that their value is one but these constants still have dimensions, or are we somehow choosing h=c=1 to be a pure number with no dimensions?

Homework Statement Suppose that m = 1 mod b. What integer between 1 and m-1 is equal to b^(-1) mod m? The Attempt at a Solution m = 1 mod b means that: m = kb + 1 for some integer k Let x be the inverse of b mod m, note: x exists since b and m must be coprime due to the previous...

1. My teacher has given me a poster board to do on magnetic energy even though she has explained nothing about the subject, nor is there anything in my book. I am looking for the formula for finding magnetic energy and examples from everyday life. All I got was 1/2BH, but I have no idea what...

Homework Statement http://www.aijaa.com/img/b/00125/3627010.jpg http://www.aijaa.com/img/b/00758/3627011.jpg Homework Equations E_k=\frac{1}{2}mv^2 \vec{F}=m\frac{\vec{v}^2}{r} \vec{F}=q\vec{v} \times \vec{B} \frac{v}{r}=\frac{2\pi}{T}=\omega The Attempt at a Solution The...

How do you convert a length which has been given in MeV ^-1 to SI units? Energy is mass length^2/time^2 so I guess it;s easy to make the steps of energy - mass - momentum etc... What about length and time? Cheers

Dear PF members, In terms of natural units the reduced Planck's constant (\hbar) is 1 ML2T-1. Now in this terminology how a magnetic field can be expressed? thanks for your reply, rajini

When using the ideal gas law equation and solving for V, with constant R = 8.314 J·mol−1·K−1, what are the resultant units? L or m3? I always remember it being in L, but wouldn't it be m3 based purely on the units being put into the equation? Other units I'm using: P: Pa (not kPa) T: K

Hi all could anyone tell me what units are used in the equation E=MC. Thx, Dave.

Units -- is this m/s or mm/s? Homework Statement N/AHomework Equations Continuity A1*v1=A2*v2 A=pi*r² The Attempt at a Solution I've solved a problem as follows (pi * 10.0mm²)(0.200m/s)=(pi * 2.50mm²)(v2) 3.20 xx/s = v2 I am pretty sure it's in m/s, but having the radii in millimeters is...

Homework Statement Well, here's the homework question: A charge Q is located inside a rectangular box. The electric flux through each of the six surfaces of the box is: phi1=+1500Nm^2/C, phi2=+2200Nm^2/C, phi3=+4600Nm^2/C, phi4=-1800Nm^2/C, phi5=-3500Nm^2/C, and phi6=-3400Nm^2/C. What is...

I am solving the Hydrogen wavefunction using FORTRAN. Now using the Euler method, I am given a solution to match which is given by u10(r) = 1.06r*exp(-3.74r) (where unl(r) = rRnl(r) in general) which says it has a normalisation chosen to match what i should get from my code. Then I use the...

I am trying to make sure that the data I read off my multimeter has the right units. I have a multimeter that is a similar model to this one: http://www.tequipment.net/BK2703B.html You can enlarge the image to see the settings. When I measure AC current, my result says "2.95" when the...

I am reading something about thermodynamics and everything are not given in SI units. In the material, they use Fahrenheit for temperature, BTU for heat, lb for mass and in^2 for area. Now I need to calculate something with the data given in those units, well, I need to apply equation for ideal...

Homework Statement Let q be the number of units in finite ring R. Show that for all a in R, if a is a unit in R then a^q = 1. Is there a way to solve this without using group theory? All I can seem to find information on is when a and m are relatively prime then a^{\phi (m)} = 1 (mod \, m)...

The definition of matter is "anything that has mass and volume". Why doesn't the definition of matter mention anything about "time". Should time be mentioned as well since matter can't exist without it? Also, If matter had its own SI unit, what would it be? Edit:: a unit that could be...

Homework Statement Does Friction have units? Homework Equations U = Ff / Fn The Attempt at a Solution I know the coefficient which is "Mew" U, has no units whatsoever but I just wanted to know if friction itself had units.

Homework Statement rearrange to make p the subject then work out the units for p R - resistance or wire A - area in m2 l - length Homework Equations R=pl/A The Attempt at a Solution p = AR/l (m2 x m2kgS-3A-2)/m Resistance is ohms which is m2kgS-3A-2 I think...

I am trying to display the dimensions of a catia part in the Cat drafting sheet.(start-mechanical design-drafting). I get the dimensions to pop up in mm but I want to change the units. I have scoured menus looking for it and I can't seem to find the option. Any help would be appreciated. thanks.

Given a field F, I know that if F is finite, then its group of units F* is cyclic. I'm trying to prove the converse: if F* is cyclic, then F is finite. I have no idea where to start; I've tried a few things and they didn't get me anywhere. I know that if F is infinite and F* is cyclic, then F*...

Homework Statement A particle experiences a variable force Fv = Fo * sin (cx) where x is displacement in meters. What units are the constants c and Fo in. Homework Equations The Attempt at a Solution Um ok...how the heck do i figure out what units they're in so i know my final...

specific heat capacity is measured in joule per gram-kelvin (J g–1 K–1). In base units it is m2 s-2 k-1. Is that meaningless to express specific heat capacity in base units? Is there an explanation? Thanks Nick

Homework Statement So I'm wondering what the units seconds/degrees squared represents? The Attempt at a Solution I know the unit of angular acceleration magnitude is degree/second squared. Are these related?

Help with units The book gives the following forumla E_0 = \sqrt {2\mu _0 c\left\langle S \right\rangle } And when it uses it in an example, the units go from: \sqrt {\left( {{\rm{H/m}}} \right)\left( {{\rm{m/s}}} \right)\left( {{\rm{W/m}}^{\rm{2}} } \right)} to V/m, with no intermediate...

Homework Statement Hi all. The title says it all: Say we have an operator - e.g. the Hamiltonian. Does this have units? I.e. does the Hamiltonian have units of Joules or nothing? Personally I think it is nothing, since it is an operator, but I need confirmation.

I don't know where to begin lol - i know first principles is where you have a general equation which can be derived to give more specific details about something. I have been told that i need to find appropiate combinations of the four defined atomic units that have the desired dimensions but i...

Homework Statement We're doing a lab and we basically had to find ln(Pv), where Pv is vapor pressure of isopropanol. Well, the pressure is initially measured in kPa, but what happens to the units if you take a natural log of that whole thing? For example, if I take ln(5 kPa), do the units...

When e is raised to a power with units of mass what is the units of the resulting solution?

I'm sorry if this is the wrong forum but in a problem I was given wavelength with the unit as an A with a circle above it, can anyone tell me what this means and how I can get it into more familiar terms (meters, for example)?

Homework Statement I don't really know if this is the right place for this question but, we were doing a physics lab and we were using measuring instruments that measure in inches and asked to collect the data for various parts of the lab. My problem is that we were asked to graph our...

I am trying to find % acetic acid by volume in vinegar. I have 8*10-4 mol/L of acetic acid in vinegar and 8*10-5 of acetic acid in the dilute sample of vinegar and water. I know that the volume/volume % is equal to the amounts of A divided by the total amounts of A and B. BUT that...

Ok, the question asks: An electron close to a large, flat sheet of charge is repelled from the sheet with a 2.1×10^−12 {N} force. Q. find the surface charge density on the sheet in C/m^2 What i did was use the formula F = qe with 2.1e-12 for the force and 6.1e-19 for the charge of an...

A possible set of units of electric field, E, in terms of base units is: a) kg x m x s^-1 x C^-2 b) kg x m^2 x s^-2 x C^-1 c) kg x m x s^-2 x C^-1 d) C x s^-1 e) N x C^-1 I believe it is E but i wondering if there is somthing I am missing. This is how I came up with that answer E =...

The cross product equals to the area of the parallelogram defined by the two vectors (at least in R^3). So if working on vectors which units v_1 = (1,2,3)m v_2 = (3,4,5)m it correctly returns the according area. However, if used to get a vector perpendicular to each of the vectors the...

Hello, I've been thinking over for some time about creating a programmable LED display. I have an EEPROM and microprocessor among other things already, so it's not like I'm buying all the parts. Ideally, this display would be viewable from up to 30-40 feet away so it will have...

So the problem is: Convert 35 km/h to in m/s. I know that: - 1 km = 10^3 m - 1 h = 60 s So I do: 35 km/h (10^3 m/1 km) (1 h/60 s) = 583 m/s But the answer is 9.7 -- What??

Which Subjects will benefit me more: -Mechanics (Extensive, sound foundation in mechanics) or -Further Pure Maths (If I take all the units, likewise, I will have a better understanding of mathematics)

Why do people use G-units? Essentially it is a ratio of the acceleration with gravity, why not use force directly? Can anyone enlighten me? Thanks.