(energy is the capacity of a physical system to perform work and,
an isolated system is a physical system without any external exchange – neither matter nor energy can enter or exit.)
so,
how is the energy of an isolated system defined?
can it even be defined in principle??
yes perhaps, because air resistance would be greater for a rough surface as compared to a smooth one.
but isn't this fact irrelevant to the case being discussed?
why?
as the rate consumption of the fuel depends only on the air resistance (which depends on the frontal area of the vehicle) and friction from the ground; why would fuel efficiency be greater if both these aspects are kept same?
why don't we see wind harnessing structures (like tiny fan-like structures) mounted on vehicles to capture the relative motion of the wind against the moving vehicle?
I had one guess that mounting such structures would increase the surface area of the vehicle and thus the air drag acting on it...
"In fine weather, the electric potential increases with altitude at about 30 volts per foot (100 V/m)...."
what hinders its practical application as a source of power, as a battery?
the wavelength of light at peak intensity reaching the Earth ~ 500 * 10^(-9) m
the power per unit area incident on the Earth due to sunlight ~ 1400 W , giving the avg magnitude of electric field = the avg magnitude of magnetic field ~ √[(4π*10^-7)*1400] = .04 V/m
how to relate the length of...
some help needed in mathematics...
having trouble in determining the resonance condition for the rod of length (l) at driving frequency (f) = 500*10^12 Hz...
please explain how to do that?
So if we have a very large array of such tiny* and thin** rods ,and some apparently perpetual source of radiation (like a star -- our sun), such that a huge amount of appropriately polarized*** radiation is made to fall on all the rods, won't this generate power perpetually in principle (as long...
if we place a very thin rod of length 'l' in front of a source of some radiation of amplitude = length of the rod (l) ,and perpendicular to its direction of propagation (assuming all the radiation to be polarized in one particular direction), :-
|...
but how to reconcile it with the fact that the position of electron inside an atom is quantized and the average separation between the electron and the nucleus cannot change arbitrarily (the radius of an atom cannot change continuously)?
one question is in the diagram itself and there is another one based on that here :- would this induced E-field (in the wires) be equal or related to the E-field component of the incident light as per the diagram?
sorry for the crude drawing
the 2 observers are measuring the average distance between the electron and the proton of the H-atom relative to themselves, not anything that is called the bohr's radius...!
would not they disagree in their answers?
wouldn't this mean that a uniformly moving observer would detect a greater...
in general, anybody in uniform relative motion must detect a decrease in length of its surrounding world...for instance, from the perspective of a very fast moving train, all the outside world appears contracted in length, and from the outside world's perspective, the train appears to be...