Recent content by Soff

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    Rotation of Vector in P: Why Divide by r?

    I attached the graphic which describs the situation with the rotation. What I want is to describe the vector in the lower part of the system in coordinates of A^{\theta} and A^{r}. The professor told me that the solution is: A^{r}=A^{x}\cos\theta+A^{y}\sin\theta...
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    Rotation of Vector in P: Why Divide by r?

    When you rotate passivly an arbitrary vector in P (which is not in the origin of a coordinate system), you will get the following new coordinates for the same vector: x'=x \cos\theta+y\sin \theta y'=\frac{1}{r}(y\cos \theta-x\sin\theta) where r is the distance from the origin to the point...
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    Schools Studying theoretical physics at the same university

    At the moment, I'm doing my Master degree in theoretical physics. I'd like to do a doctoral program in the field of quantum field theory. My partner is also doing his Master degree at the same university like me (in Switzerland). He is more interested in the field of astrophysics. We are...
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    Fortran Debugging Merge Sort Program with Fortran 90

    Okay, I started again. This is my improved version (but still not working!): program sorting integer :: d,length,center,t,i,n,m integer :: a(128), b(128) !List of numbers Print *,'How many numbers would you like to type in?' Read(*,*)d Print*,' Enter the values, separated by...
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    Fortran Debugging Merge Sort Program with Fortran 90

    I'm trying to write a Merge Sort program with fortran 90. However, this is what I already could do: program sorting integer :: i,ialloc,error,n,d integer, pointer :: a(:) Print *,'How many numbers would you like to type in?' Read(*,*)d Print*,' Enter the values, separated by...
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    Bunch of Nuclear Physics Question, Please help me.

    There are following fundamental forces: Gravitation: long distance force electromagnetic force: Coulomb law Weak force: is important in beta decay Strong force: holds nucleons (proton, etc.) together Since the electrons are kept near the nucleus because of the attractive Coulomb...
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    Theoretical Physics or Robotics

    Hmm, I guess it advisable to study theoretical physics before starting a career in an experimental field. Are you studying physics at university? Are you an undergraduate?
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    Springs and friction and energy, etc.

    I'm not sure if I understood the problem. Why is the problem called Springs and FRICTION and energy? However, I would start with the loop: You know that in the look, the gravitational potential is equal to the energy of the block. Therefore: E_{kin}+m\cdot g\cdot h\cdot= U_{grav}...
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    Wormholes, parallel universes, negative mass

    I think if we can answer these questions, we would know a lot more about our universe. As far as I know, there are some calculations which show that the existence of a wormhole to a parallel is indeed possible (Hawking,...). However, it's not that easy... I assume that we must use a enormous...
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    Ways to Destroy Earth/Life on Earth

    As you may know, our sun is going to explode in about five billion years. Surely, that must be the end of our live on earth. The only way of surviving is to escape. However, I think it is highly probable that we're going to destroy the Earth much earlier. Since our climate is changing, I...
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    Should I Take GRE and TOEFL for Doctoral Program in Canada?

    I found an article in the internet which states that TOEFL is a level B2 test while CAE is a C1. Therefore, I think the CAE exam should be the more difficult one. However, do you know if the American and Canadian universities do accept the Cambridge Certificate?
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    Should I Take GRE and TOEFL for Doctoral Program in Canada?

    Okay, I think I will do both tests... Yet, I've got another question: When you talk about the GRE, you mean the subject test, do you? I read on the homepage of the GRE examinations that there exists also a more general exam. Is it enough to do the subject test, or is it advisable to do the...
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    Should I Take GRE and TOEFL for Doctoral Program in Canada?

    I have a Bachelor degree in Physics and will finish my Master studies in approximately 3 semesters time (quantum field theory). Here at the university in Switzerland, nobody cares about tests like GRE and TOEFL. But since I'm planning to apply to a doctoral program in Canada (maybe Toronto or...
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    General Relativity and Quantum field theory

    Thank you for your advices! I really don't want to do some kind of pop science, I'm more interested in the theoretical physics of General Relativity and Quantum field theory. So, I think (after reading your tips) New Zealand, Canada or UK would be the best. I already know it's hard to find...
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    What is the Meaning of Gamma_{1} in Nuclear Physics?

    I finally found the right solution: Since the alpha particle has a very long lifetime, it randomly decays. Therefore: \Gamma_{\alpha}<<1 On the other hand, a neutron decays very easily, what means: \Gamma_{n}>>1
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