# Tagged Questions

Units are standards of measurement used for different types of quantities.

463 views

### What is the relationship between the magnetic units oersted and tesla?

How are the units oersted and tesla related? For example, how would you express $20\:\mathrm{Oe}$ in tesla?
163 views

### Why do we not use the SI system for distance in space?

One of the closest stars to Sol is Alpha Centauri at 4.367 Ly according to wikipedia. Why do we not say that it is 41.343 Peta-meters rather? (4.367 Ly = 41.343 Pm) Why does Light-years or Parsecs ...
3k views

### Is it mathematically wrong to use units instead of words/parameters/names in equations?

In equations that have quantities with physical dimension. Example: $\mathrm{Force} = (\mathrm{mass})(\mathrm{acceleration})$ or $F=ma$ I know that we use that (mass, force...) to help what we ...
12 views

### Units for stiffness term of radial bearing

I've come across a 4x4 stiffness matrix for a radial bearing with rotational stiffness. The stiffness matrix would look like ...
53 views

### What is W.u. as a unit in a nuclear physics context?

In a recent paper (doi/arXiv), of note for causing this recent tussle over its handling by science news media, there's some strange units I can't quite puzzle out. Specifically, the abstract contains ...
74 views

### In the equation $F = kma$ , what's $k$? [duplicate]

Actually I want to know that what is $k$ & why it's SI unit is set to 1. Also if it's can be expressed in SI units , that means it can be converted into CGS etc. units .. So what's the value of $k$...
43 views

### How extremely low temperatures (near absolute zero) are actually measured [closed]

How do the industrial or laboratory thermometers for this purpose work like: what effects are based on, what are other alternatives how accurate they all are
32 views

### Specific Heat of tissues vs kcal (Weird Thermodynamics question)

I'm a YouTuber who over-examines video game physics for the purposes of both education and entertainment, and I've run into a bit of a snag while researching my next video. I'm looking into heating ...
51 views

### Is this differential equation (for damped & driven physical pendulum) physically valid?

Following is the equation of motion for a physical pendulum which is damped and driven by a force of frequency $f$: $$\frac{d^2 \theta}{dt^2} + b \frac{d\theta}{dt} + sin(\theta) = Tsin(2\pi ft)$$ ...
48 views

### Defining Thermodynamic beta in unit of second

If I define Thermodynamic beta in unit of second. Does this mean that: Boltzmann constant $k$ is unit-less? $T$ is in units of frequency (Hz) or Kelvin $K$? In this case, is defining Thermodynamic ...
41 views

25 views

### how sound quantity in a period of time is measured by? [closed]

Let's suppose that I'm singing for 10 minutes and I obviusly produce some sounds, and let's imagine that I hold an instrument for measuring the amount of sounds produced within that period of time. I'...
50 views

### What does J cm-1 stand?

For an optical component, I got following number as an optical damage threshold from the company, damage threshold = 10 Jcm-1,20ns, 20Hz It looks like 20ns is ...
43 views

### Where is the periodic nature in the Cs atomic clock? [closed]

In case of pendulum clock,lets say one swing ticks one second..but what is the analogy in case of CAESIUM atomic clock? Is 9,192,631,770 ticks is equivalent to one tick in pendulum clock? And how we ...
25 views

### Why is metre defined in terms of distance covered by light in 1 second? [duplicate]

Why is the unit of length defined with the help of unit of time? (1m=x covered by time in 1/3*10^8 s) Isn't length a fundamental unit too, why is it defined in terms of an other unit?
33 views

### What would be the standard for the unit of pressure Pa or MPa?

Me and my friend are doing a project and in our result we shall provide a plot, and on our axes we are going to write out the units. My friend wrote "xx MPa", claiming it was standard in reports to ...
163 views

### What is the dimensional formula of angular velocity?

I have problem to determine the dimensional formula of angular velocity. My friend said that the dimensional formula of angular velocity is $T^{-1}$. It's come from rad/s, rad is dimensionless, the ...
I have noticed three ways to write the 4 momentum vectors: $P = (E/c, \vec{p})$ $P = (E, \vec{p})$ $P = (E, c\vec{p})$ I know how to derive equation 1, and as far as I know, one can use the ...