Physics, 04.10.2019 19:30 jbdelarosa
Do the conduction electrons in a copper wire act quantum mechanically or not? roughly speaking, quantum mechanics comes in when the de broglie wavelength of an electron is comparable to or longer than the spacing between atoms. the lattice constant (roughly the spacing between atoms in a crystal) for copper is about 4 x 10-10 m. the drift velocity of electrons is typically less than 102 m/s under household conditions (b) what about atoms in the interstellar medium? here we want to compare the average spacing between atoms (they move! ) to the de broglie wavelength of an atom. the interstellar medium is mostly hydrogen at an average density of order 1/cm3 and temperature about 3 k. in this case you' need the thermody- namic resul p/(2m)(3/2)kt, where k is boltzmann's constant (c) now let's switch gears to talk abou the uncertainty principle when ligo detects gravitational waves, it is measuring displacements of its test masses of order 10-18 m. the test masses are about 40 kg. what is the minimum uncertainty induced in the velocities of the test masses?
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Physics, 21.06.2019 23:00
Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?
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Physics, 22.06.2019 09:40
(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)
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Physics, 22.06.2019 11:30
Which accounts for an increase in the temperature of a gas that is kept a constant volume
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Do the conduction electrons in a copper wire act quantum mechanically or not? roughly speaking, qua...
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