Heat, Work, and Energy

[steve_bank]

Pulse a laser trough a block of glass and there is a time delay through the glass. That measured time delay will be the same in any frame.

I don't think that's correct. Moving objects get shorter in the direction of travel. The measured time for light to go through the glass will vary from one frame to another depending on the length of the glass in each frame.

Getting off topic.

The fact that C is not relative to source velocity is what makes it all work theoretically and physically. For example RADAR.

C is defined in a vacuum. In air it is slightly slower, in a dielectric like glass slower still.

In your inertial frame as you accelerate seconds, meters, kg, and C do not appear to change. To an observer in a frame your time appears different

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[steve_bank]

Multiple choice questions.

In terms of thermodynaics

You put 2 liters/second into a pipe and get 4 liters/second out.

Do you
A Assume the excess water is coming from a hole in the space time continuum.
B. Assume God did and make it a holy site to god.
C Assume the excess water is spontaneously coming fro nothing,.
D Assume water is getting into the pipe from somewhere else in the plumbing system.

E. I assume there is no excess water. The density of the water goes down in inverse proportion to the volume, which increased because while it was in the pipe the pressure of the water went down or its temperature went up or some combination thereof. PV = nRT.

That is the ideal gas law, it works at low pressures and temperatures. Actually it is PV = nRTZ where Z is the comprehensibility factor. The ideal gas law ignores the finite size of gas molecules and atoms. Z is empirically determined.

There is a saying about a little knowledge being dangerous.....

I worked on IR video systems in the 80s that used compressed Argon to cool a detector to reduce noise. Compressed Argon gas sprayed on the detector condenses and then evaporates.

Nitrogen has a lower temperature aground 77k as I remberr and Argon 87k but Argon has a higher heat capacity.

 

[steve_bank]

The answer is simple. Input Power = Output Power + Losses,.

One can overthink a problem. At the macro Newtonian scale Laws Of Thermodynamics rule.

Energy, heat, work, mass, conservation of energy and mass, and no lossless systems.


Without knowing anything about fluid mechanics, turbines, and electrical generators.

Required input power is output power/efficiency.

Water power in = 100 Megawatts/0.9 = 111 Megawatts

Making a broad assumption that the bulk of losses show up as heat the heat generated is 11 megawatts.


Find time to free fall 200 meters
h = .5*g*t^2
t = sqrt(200/(.5*9.8) = 6.3887656 seconds


Find velocity
v = g*t
v = 6.3887656 * 9.8 = 62.609903 meters/second

Find mass of water required
kinetic energy = .5*m*v^2
m = 111megawatts/(.5* 62.609903^2) = 5439000 kilograms

Find volume flow rate
At standard temperature and pressure density of water is approximately 1000kg/m^3
volume flow rate = 5439000/1000 = 5439 m^3/s



The discharge rate at the mouth of the Columbia is 7550 m^3/s

The Grand Coulee dam on then Columbia has a capacity of 6800 megawatts and a height of 168 meters.

Without a grounding in Newtonian mechanics and thermodynamic jumping to quantum and relativistic mechanics can lead to misinterpretations.


LOT does apply but the formulation changes.

In a photo detector quantum efficiency is photons in versus electrons out. At the quantum scale the efficiency of a photo detector can not be >= 1 as in any Newtonian scale system like a power pant.

For a photo voltaic solar cell it is( incident photons in watts) X (efficiency) = (outpit in watts), terminal voltage times current.

Planck’s constant expresses a photon’s energy which takes into account frequency..

h = 6.62607015×10−34 J⋅Hz−1 energy in joule

In solid state photo detectors the energy of photon and the band gap energy of the material are expressed in electron volts.

An electron volt (eV) is a unit of energy, specifically the amount of kinetic energy gained by a single electron when it accelerates through an electric potential difference of one volt. It's a very small unit, commonly used in atomic and nuclear physics.

One eV is equal to 1.602 x 10⁻¹⁹ joule

Energy always reduces to Joules. eV is a different way of defining energy, IOW the capacity to do work.

In photo detectors it is said when the energy of the photon equals the energy of the material band gap absorption occurs, both in eV. Not the same context as saying coal has energy in J/kg, but energy non the less..