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    I General solution of the hydrogen atom Schrödinger equation

    Hello everyone! I have two questions wich had bothered me for quite some time. I am sorry if they are rather trivial. The first is about the general solution of the hydrogen atom schrödinger-equation: We learned in our quantum mechanics class that the general solution of every quantum system is...
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    B Gravitational force between two masses

    Hello everyone. Probably this question is trivial, but nevertheless I am confused about newtons law of motion: $$F=G\frac{m_1m_2}{r^2}$$ Now, some sources say, that F is the force between the two masses m1 and m2. Other sources say, that F is the force that m1 exhibits on m2. But isn’t this a...
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    Confusion about Enthalpy

    Hello everyone! I have a course in thermodynamics this year, and there is a question about enthalpy that I cannot answer: given the definition of enthalpy H=U+PV and the integral form of the internal energy U=TS-PV we conclude that H=TS. We normally say that enthalpy equals the heat exchanged in...
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    Problem in solving differential equation

    Hello everyone! I was studying chaotic systems and therefore made some computer simulations in python. I simulated the driven damped anhatmonic oscillator. The problem I am facing is with solving the differential equation for t=0s-200s. I used numpy.linspace(0,200,timesteps) for generate a time...
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    I Rosetta orbits and phase space

    I was recently working on the two body problem and what I can say about solutions without solving the differential equation. There I came across a problem: Lets consider the Kepler problem (the two body problem with potential ~1/r^2). If I use lagrangian mechanics, I get two differential...
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    I The Trapping Region of the Lorenz equations

    I was dealing with nonlinear systems of differential equations like the Lorenz equations (https://en.wikipedia.org/wiki/Lorenz_system). Now there is a trapping region of this system defined by the ellipsoid ρx^2+σy^2+σ(z-2ρ)^2<R. I wondered how this region is found and I found out that a...
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    I Confusion about position state kets

    I am a bit confused about how kets in dirac notation are working. I read on wikipedia, that kets are linear, so |a*Φ>=a*|Φ>. Also I read (https://ocw.mit.edu/courses/physics/8-05-quantum-physics-ii-fall-2013/lecture-notes/MIT8_05F13_Chap_04.pdf) that this is not true for the position state ket (...
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    I Rotation of functions

    I was solving a problem for my quantum mechanics homework, and was therefore browsing in the internet for further information. Then I stumbled upon this here: R is the rotation operator, δφ an infinitesimal angle and Ψ is the wave function. I know that it is able to rotate a curve, vector...
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    Energy in different inertial frames

    Lets neglect conservation of momentum and assume that all frames of reference are inertial. Now imagine three objects: the sun, the earth and an asteroid. In the inertial frame of the sun, earth and asteroid are flying towards each other ( velocitys v and -v). Now imagine you are standing at...
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    Clearing a wall with a golf shot

    Every trajectory follows a parabola if we neglect air resistance. So we can calculate the maximum distance in x direction s_max. Also we can determine the time it takes to hit the ground again t_max. If the ground is everywhere the same height, I can assume that at t_max/2 the height (s_y) is at...
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    I Radius vector in cylindrical coordinates

    I am starting to learn classical physics for my own. One exercise was, to calculate the vector r (see picture: 1.47 b). The vector r is r=z*z+p*p. I don’t understand this solution. My problem is: in a vector space with n dimensions there are n basis vectors. In the case of cylindrical...
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    Current produced by photolectrons

    Homework Statement In perspective to the photoelectric effect I found following question: Electric current is charge flowing per unit of time. If we increase the kinetic energy of the photoelecrons (by increasing the energy of the incident photons), shouldn’t the current increase, because the...
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    Statistics physics problem -- atom is in the ground state or excited state?

    I am learning for my exam in particle physics. One topic is statistical physics. There I ran into this question: Consider an atom at the surface of the Sun, where the temperature is 6000 K. The atom can exist in only 2 states. The ground state is an s state and the excited state at 1.25 eV is a...
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