Recent content by bubsir

Direct gravitational measurements of subatomic particles seems impossible. Has it been done/tried? The mass of the proton as I know it is always "indirectly" determined by (for example) bending a beam of charged protons in a magnetic field.

Window insulation is a big business. They are rated by "U-value" Watts/m2/K (the inverse of "R-value" In the USA, R-values are given in hr.ft2/BTU). Adding double panes helps by about a factor of 2. Adding a "fill gas" (typically argon) is common. And another gain is adding a transparent...

“Young man, in mathematics you don't understand things. You just get used to them.” ―John von Neumann

I prefer an axiomatic approach to mathematics. Anyone who wants to introduce a "new" mathematics needs to start with their "new" axioms. I was not able to find an easy link to Mr Wildberger's axioms and therefore wouldn't suggest the work to others as anything more than entertainment. In his...

The nice thing about the definition of derivative AND f(x) is that you only need to find the difference, not the actual function.

' of course the a in this definition is not the constant in the definition of f(x)

Seems dλ/dθ should be a large number if the beam 3 cm and resolution is sub nanometer.

"how can i use epsilon delta to prove differentiability?" Use the definition of the derivative.

You must set up a limit, epsilon delta style

To get an answer it just needs to be more specific: Say the room is 4x4x3meters (3 tall) and the object has a one meter square surface facing you and it's in the middle of the room so you are 2 meters away (at best!). We want to know how hot this surface need to be to incinerate you. I'll assume...

I can't say I read every comment so excuse me if I missed something. The terms "thick" and "thin" have special meaning when applied to lenses as there is an entire field of "thin lens" design techniques. But when it come to mirrors - to the best of my knowledge - there is only the physical...

An analog output is a voltage or current - if it changes (volts or amps) both are also "signals." For a specific implementation you can set up a "current" or "voltage" based output. A current based output is easily converted to a voltage by driving through a resistor. Voltage to Current requires...

In the case of "gravitational energy," or potential energy in general, energy is not "localized" but is "contained" in the associated field (gravitational, electric, magnetic,etc).

I'd just start with no, I don't think your description is a good one so your understanding probably isn't either. Energy is thought to be "exchanged" between different types: potential, kinetic, chemical and so on. Conservation says you don't create or destroy it; the sum of all the energy...

Hello world. Old geek with nothin' better to do. I don't like doing peoples homework but I do like to tutor and teach.