Tagged Questions
-1
votes
1answer
48 views
Convert units from cal cm^-1 day^-1. to Wm-2
I am trying to calculate the energy budget of a water body and the last term I'm trying to calculate is the energy advected from the water body ($Q_v$). This equation is given by:
$Q_v = V ( (T_1 - ...
0
votes
1answer
58 views
Magnetic Field and the Speed of Light
Is it just a historical choice that both magnetic field and the Lorentz force equation include the speed of light?
I figure that whoever wrote up the equations (in cgs!) could have put both factors ...
3
votes
1answer
48 views
CGS Units for Magnetism
Why does the formula for magnetic field force include the speed of light in the denominator in cgs units? Where does the extra $c$ go in SI units?
0
votes
1answer
45 views
Rotation System Dynamics - Unit conversion issues
I'm having issues with unit conversions when for rotational systems. All of my components (spring, mass, damper) come in Imperial units, so I did all my calculations in Imperial. When I convert to ...
0
votes
3answers
147 views
Temperature in CGS (Gaussian) units
I've been struggling with conversion from Gaussian to SI units for sometime, trying to figure out how derived units in CGS (current, charge etc) relate to the SI units.
But I couldn't find any ...
0
votes
1answer
168 views
CGS Units to SI Units
This may be a stupid question but I am having trouble getting the same result in CGS units as I would if I used SI units for a unitless calculation.
I have to calculate $E_c=\frac{m_e c\, ...
2
votes
6answers
343 views
Confused about unit of kilowatt hours
So I am a little confused on how to deal with the Kilowatt hours unit of power, I have only ever used Kilowatts and I have to design a residential fuel cell used as a backup generator for one day.
...
3
votes
3answers
104 views
What is the missing proportionality constant in the magnetic levitation formula?
The formula for magnetic levitation is
$$ B \frac{dB}{dz} = \frac{ \rho g }{\chi} $$
but as always, I have a hard time figuring the units in SI. The left hand side is $\mathrm{T^2 /m}$, while $\chi$ ...
3
votes
1answer
105 views
Help on unit conversion problem
This is a problem from school. I will show my attempt.
The question:
"The gas constant for dry air R is 287 $\frac{m^2}{s^2*K}$. Assuming the temperature is 330 K and the pressure is 1050 hPa, what ...
1
vote
1answer
90 views
Conversion of the units BeV (US) and GeV (UN)
What is the difference in the definition of a billion electron volts in United states (US) and United Nations (UN)?
When the US people say billion, do they mean $10^{12}$ or $10^9$?
0
votes
1answer
80 views
Is this a correct addition to a pipe friction loss calculation?
I've been using this online calculator to work out the difference in pressure and flow between two ends of a pipe:
Pipe Friction Calculation for Fluid Flow in a Pipe
So far most of it makes sense, ...
2
votes
1answer
2k views
How much is 1 electron-volt (eV)?
I am interested in knowing how much is one eV of energy. Everywhere I found are the technical definitions. Can anybody please tell me how much is this much energy. I need something which I can feel. I ...
0
votes
1answer
434 views
Question Based On Units And Measurements Involving Lengths [duplicate]
The below is the sixth question of the very first chapter from halliday and resnicks fundamentals of physics text,which i'am not able to comprehend.
Harward Bridge,which connects MIT with its ...
4
votes
3answers
176 views
What is a “measure equation” as mentioned by this TeX Users Group guide?
In this TeX Users Group (TUG) document, Typesetting mathematics for science and technology according to ISO 31/XI by Claudio Beccari, the author makes various typesetting recommendations including:
...
0
votes
2answers
689 views
static friction problem without mass
I am having trouble with a physics problem. The problem is as follows:
A car is traveling at 54.0 mi/h on a horizontal highway.
A) If the coefficient of static friction between road and tires on a ...
1
vote
1answer
305 views
Converting Notes to Milliseconds
Given a note duration (whole, half, quarter, etc.), a tempo (in beats per minute), and a time signature, how long does that note last in milliseconds?
2
votes
2answers
486 views
Fundamental units
Is it right that all units in physics can be defined in terms of only mass, length and time?
Why is it so? Is there some principle that explains it or is it just observational fact?
-1
votes
3answers
271 views
Help getting the distance an object has moved
What is a distance an object went through at the speed of 14hm/min for 6 hours?
I am having problems with conversions.
First, I tried passing 14hm/min to m/s. I did it alright. But now I am unsure. ...
