Units Definition and 975 Threads

This was part of a problem found in my book. Not really homework problem so I'll post it here. Electric field on a certain region is (E is a vector of x,y, and z components) (t is a independent variable in meters) what kind of unit is this? I do realize unit of E is N/C or also in...

This should be very easy but I can't see what I am doing wrong... V_t=\mu .d where vt = tangential speed (in km/s) d = distance (in km) mu(radian/sec) Now by converting I should get V_t=4.74\mu .d vt = tangential speed (in km/s) d = distance (in parsec) mu(arcsec/yr) but...

I'm using the equation: E=gamma*m I want to know what the units of each of the quantities are. If I want to calculate the Lorentz factor, then do I need to make sure that both the Energy and mass have the same units? I am also using the equation for length contraction: L=L0*gamma Do I...

Apologies for the newbie question, but when it is written km-1 does that mean (103m)-1 or 103(m-1)? Thanks in advance!

I need to calculate the mean square speed of molecules in an ideal gas. Mean square speed is equal to 3RT/M, where M is the molecular weight. But what units do I use for the molecular weight if I use 0.08206 L.atm/(mol.K) as R? Thanks a lot.

Homework Statement Got a charge of 2CGSEm need to find it in SI Homework Equations 1C=2.998*10^{9}CGSE The Attempt at a Solution Just a plain question, I get q\approx6.66*10^{-10} Is that correct?

Homework Statement Determine the units of the quantity described by each of the following combinations of units: a. kg (m/s) (1/s) b. (kg/s) (m/s²) c. (kg/s) (m/s)² d. (kg/s) (m/s) Homework Equations n/a The Attempt at a Solution I would attempt to solve the problem, but I...

Homework Statement (a) A ball of mass 0.4 kg, initially at rest, is kicked directly toward a fence from a point 20 m away, as shown below. The velocity of the ball as it leaves the kicker’s foot is 17 m/s at angle of 42◦ above the horizontal. The top of the fence is 5 m high. The ball hits...

Hi all, I'm running a microcontroller that has me program times in 8.68microsecond units, and I'm having an issue converting 10ms to 8.68us units, then counting a number (scalar) then taking that number and getting RPMs from it. Here's what I have so far: 10ms = 10,000us...

Could the Ampere be given in units such as N.s.m^-1 ? Would this be correct, i originally just thought it would be N.m^-1

Is it possible to adjust the length of the meter, the length of time of a second, the amount of mass in a gram and the other basic SI units in a way such that all the fundamental constants of nature have integer values?

Homework Statement A company can do 300 units per week at a weekly cost per unit of $58 for labor and supplies. If the charge is $100 per unit, then it would have clients for 300 units. However, for each $5 price increase, it could expect to have 10 fewer units. Homework Equations...

Homework Statement Hi I am told that 1 (E)1/2 = 9.045Å-1, where E is the energy in meV. How do I find out what 1 meV is in Å from that? All I can get is the correspondence between meV and Å-2, not meV and Å.

What would the units be on the curvature of spacetime? G(curvature)=8πGT/c^4

I didn't use the template because I'm trying to understand a concept which applies to many problems rather than just one. Many times in exercises I am assigned, I am asked to convert from one unit of measurement to the other. For the most part it's easy to understand, but what confuses me is...

Time standards are now based on atomic clocks. A promising second standard is based on pulsars, which are rotating neutron stars (highly compact stars consisting only of neutrons). Some rotate at a rate that is highly stable, sending out a radio beacon that sweeps briefly across Earth once with...

About 6 minutes ago I thought of this, and I want to check if it is true. Is the kilogram and the second a basis for all units in existence? That is, can all units be derived from these two? I can't think of any other units that are independent.

I have a quick question about the units used in high energy physics. In natural units, c = h = 1, but I keep seeing time referenced as t=\frac{1}{m^2}. I figure there's 2 h-bars on top but that still leaves s^2. Can someone straighten me out here? Thanks!

Homework Statement So I'm going over the simple yearly interest formula A=P(1+r)^t, where 't' is in years, 'P' is in dollars and is the size of the initial investment, 'A' is in dollars and is the total interest earned in a given period of years, and 'r' is the rate at which the investment...

In doing some research, I cam across an equation for instantaneous radiated power, with the CGS units "erg/(sec rad cm)", rad being radians (not rad the unit for radiation exposure). Try as I might, I'm not able to come up with a way to convert it to the SI units for watts. Does anyone know...

Homework Statement the title says it all, we are required to show that the units of RC are the same as the units of time. ie. iohm * 1 farad = 1 seconds Need help thanks Homework Equations The Attempt at a Solution

Hi, I'm trying to calculate the minimum mass of a star, where M=PV³/2πG The values I've been given are V=400km s^-1 and P=34.4 hours. Does this mean that I have to convert these values to SI units, i.e. give the values in terms of metres and seconds rather than km and hours? This would...

I know that the SI unit of Intensity is W/m^2. I came across one more unit of intensity -> AU..but could not get much on that. Can anybody tell me the conversion formula ( from SI to AU ) ?

I found this on Wikipedia for the equation relating to centrifugal force. F = d/dt (m*v) So I have my mass and velocity but I just multiplied the two, that can't be correct can it. You have to derive something I imagine. Also would the units just be in lbs or Newtons. I'm using feet/s...

Hi What units does incident light have in UV spec? Is it joules? Transmission is defined as transmitted light / incident light so any units of light simply cancel out to give a unitless number. I presume the original units were joules as light is EMR? Perhaps its more complicated than that...

Homework Statement Wave vector = k, what's the unit? http://en.wikipedia.org/wiki/Uncertainty_principle#Robertson.E2.80.93Schr.C3.B6dinger_relation" In that equation, what is the name of the h (modifoed h) and what's it's units? Homework Equations k = p/h (not a normal h) The...

A Jigger is three mouthfuls. A hogshead is two barrels. A furlong is "The distance a plow team could be driven without rest." A mile is eight furlongs. A league is "intended to be an hour's walk." I'm not even going to get into the mess that is the definitions for weight...

So, we start with special relativity in c = 1 units. The equations for energy and momentum can be written as: E = E_{0} \gamma \vec{P} = E_{0} \gamma \vec{v} where E_{0} is the rest energy, \gamma = \frac{1}{\sqrt{1-v^2}} and \vec{v} is the (dimensionless) velocity. We...

Learning a bit more about Planck units, it looks like a number of arguably arbitrary, or at least pragmatic, choices had to be made, regarding using G versus 4piG, using 1/4piEpsiolon0 versus Epsilon0, and so on, but in the reading I don't see any question that h/2pi, rather than h, is the best...

I have some things that have a 7% chance of being blue, 10 of these things are put in a box. What is the percent chance that the box will have exactly one blue thing? Two blue things? and so on.. I have simulated this and came up with the following (all appx) 0 - 37% 1 - 37% 2 - 18% 3 -...

I'm trying to make a table in LaTeX in which all the entries of a column have the same units, without having to type them for each column. (Before you say it, yes, I know I could just put the units in the column heading, but I don't want to). I tried: \documentclass{article}...

Homework Statement Example: If the tension in a string is 25N, the square root of that tension would be 5 ...what?

okay we know that velocity is in meters per second and that acceleration is in m/(s^2) , so if I take the derivative of velocity with respect to time i get acceleration . but just looking at the units , if i start with velocity m/s (ms^-1) this might sound crazy but can i just take...

riddle question " max profit + units " Homework Statement There is no demand for a new brand of mobile phones if the price is 20 $ or more. For each drop of 1 $ in the price, the demand increases by 500 units.The cost of producing x units is (12x + 2000)$. How many phones should be produced...

Homework Statement I'm dealing with densities of liquids. When using the formula P = Patm + ϱgh, where ϱ is the density of the liquid, what should the units of ϱ be? Homework Equations The Attempt at a Solution I have P in kPa, so just looking at the units gives: kPa = kPa +...

Homework Statement First of all, this is my first post here, so I apologize if I format things incorrectly. I'm working on a Matlab script to evaluate the tunnel ionization rates via the PPT model given the correct set of input parameters. The rate equation I am using contains equations...

Homework Statement I am trying to integrate from 0 to 10 ft -4x^2/2+4x. I am solving for deflection. The forces are in kips. Somehow the book ends up with k-ft^3. I don't understand how I would carry units in an integration. Any help please? Homework Equations The Attempt at a...

A Typo? Homework Statement The question is: Which of the following are units of momentum? The possible answers are: A. N x m B. kg x s/m C. kg x m^2/s D. J x s/m E. kg x m^2/s^2 Homework Equations The Attempt at a Solution Is there a typo on this homework question? I thought...

Hello everybody! I found a great resource which helps me a lot solving unit conversions. I could find more than 5000 units and 70000+ unit conversions and a lot of discussions on important unit conversions. Here is the link http://www.converter.pk

ok, let's say i am plotting a graph of Energy VS voltage so my units will be Joules VS Volt so my gradient will be Joules per voltage but what if i plot ENergy VS square root of VOltage? will it become Joules VS VOLT1/2 so gradient = Joules per Volt1/2 ? my lecturer once said...

hello, I'm new to the forums. Can someone help me with integrating kinematics problems? For example velocity= Be^(-rt), where B= 3.00 m/s and r=0.500 s^-1. i don't understand how the integral's unit becomes m (since the integral of velocity is displacement). someone help me! thanks

Homework Statement Prove that the ring R of polynomials with real coefficients (i.e. f(x) = a0 + a1x + ... + anxn, ai real, are elements of R) has only the constant term a0 as the group of units, providing the constant term isn't zero.Homework Equations u is a unit if there exists a v such...

If a student spends roughly 28 hours per week studying, and has 13 units , would you say that this is enough study time for the average person? With classes that are math, science related. This pertains to a student at a 2 year college? Do you believe it would it be different for a...

Hi =D I was thinking about the physical units (g, m, s, K, J, A, V, etc). I know we got a thing in physics called dimensional analysis, so you analyse some variable that you know it depends on other variables and the two sides of the "equation" (I mean a equation with the proportional sign...

How would I show that every unit in Z[sqrt(2)] is of the form +/- (1 +/- sqrt(2) )^n ? I can show these are all units, but I can't show every unit is one of these. From some research, I'm aware this is a special case of Dirichlet's Unit Theorem, but that is far above the level I'm working at...

Recently I found this: Note the number - 15360*pi = 48254... This is a biggest number in Planks units I have ever seen In Planks units, what is the biggest dimensionless you have even seen? Anything bigger than 50'000?

Hi friends, I have a question regarding MD simulation using a LJ potential. If I take the e and sigma parameters in the LJ potential to be that corresponding to argon, and calculate some thermodynamic quantity can I convert the value of that thermodynamic quantity...

Excuse the question but I am stuck on this for the past hour. Im studying Zweibach's "A first Course in String Theory". From the Nambu-Goto Action he derives the wave equation which consists of the term \frac{\partial \mathcal{L}}{\partial \dot{X} ^{\mu}} &=...

Ok, I am thinking that I should probably move this to the Coursework area. I am not sure how to do that or if I even can... My bad...Excuse the question but I am stuck on this for the past hour. I studying Zweibach's "A first Course in String Theory". From the Nambu-Goto Action he derives the...

Note this is more of a coursework theory question then a specific homework question. I am learning about E and B fields and electromagnetic waves. A common EM figure I find is the propagation of a photon where the E and B field propagate through space as seen in the following link...