Recent content by kudoushinichi88

  1. K

    Showing that the Einstein Tensor has zero divergence

    Homework Statement We have R_{iklm;n}+R_{iknl;m}+R_{ikmn;l} \equiv 0 Show that by multiplying above with g^{im}g^{kn} we'll get \left( R^{ik}-\frac{1}{2} g^{ik} R \right)_{;k} 2. The attempt at a solution g^{im}g^{kn} \left( R_{iklm;n}+R_{iknl;m}+R_{ikmn;l} \right) \equiv 0...
  2. K

    Solving 4-Momenta Problem for Toy Theory: A + A -> B + B

    Terribly sorry, I should've made my question clearer. All of the ps in my post refers 4-momenta while \vec{\textbf{p}} refers to 3 momenta. I'm working in the CM frame. In this scattering reaction the subscripts refers to the particle in the reaction as follows: 1 + 2 -> 3 + 4 @andrien, you...
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    Solving 4-Momenta Problem for Toy Theory: A + A -> B + B

    Homework Statement For a scattering problem A + A - > B + B in the Toy Theory, Need to show (p_4-p_2)^2-m_C^2c^2=p_4^2+p_2^2-2p_4\cdot p_2 = -\vec{\textbf{p}}^2(1-\cos\theta)Homework Equations this is assuming m_A=m_B=m and m_C=0The Attempt at a Solution p_4^2+p_2^2=2m^2c^2 but I'm not sure...
  4. K

    A Tensor Problem: A skew-symmetric tensor and another tensor

    Here's what I have so far: (B_{ij} B_{kl} + B_{il}B_{kj})A_{ik}\\ =B_{ij} B_{1l}A_{i1}+B_{ij}B_{2l}A_{i2}+B_{il} B_{1l}A_{i1}+B_{il}B_{2j}A_{i2}\\ =B_{1j} B_{1l}A_{11}+B_{2j} B_{1l}A_{21}+B_{1j}B_{2l}A_{12}+B_{2j}B_{2l}A_{22}+B_{1l} B_{1l}A_{11}+B_{2l}...
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    A Tensor Problem: A skew-symmetric tensor and another tensor

    Homework Statement If A_{ij} is a skew-symmetric tensor, and B_{ij} is a second-order tensor, evaluate the expression (B_{ij} B_{kl} + B_{il}B_{kj})A_{ik} and express the final answer in its simplest form. Homework Equations For a skew-symmetric tensor, A_{ik}=-A_{ki} The...
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    How to Calculate Vapour Pressure Changes with Temperature?

    Homework Statement This is problem in Mandl's book on Stats Phys; The vapour pressure of water at 298.15 K is 23.75 mmHg. What is the vapour pressure of water at 273.16 K, given that the latent heat of evaporation of water at 298.15 and 273.16 K is 43,991 and 45,049 J/mol respectively?Homework...
  7. K

    Solving Schottky's Defect Homework with 3 States

    Homework Statement A ‘lattice gas’ consists of a lattice of N sites. Each of these sites can be empty, in which case its energy is zero, or occupied by one particle, in which case its energy is e. Each particle has a magnetic moment of magnitude μ which in the presence of an applied magnetic...
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    Amazing water trick? Is this physically possible?

    Amazing water trick?? Is this physically possible?? This vid has became viral recently. So is this physically possible?! I am skeptical from the way the water behaves when it washes away from the cup's shape. And the fact that the rest of the guy's uploaded videos are of animation stuff...
  9. K

    How Does Relativistic Kinetic Energy Derive from Force Integration?

    In the derivation of the relativistic kinetic energy, K=\int_{x_1}^{x_2}F\,dx = \int_{0}^{v}\frac{d}{dt}(mv)\,dx = \int_{0}^{v}(mv\,dv+v^2\,dm) here, my lecturer told us without showing that mv\,dv+v^2\,dm = c^2\,dm Can someone please give me hints on how to combine these two integrals? I...
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    A few integration by parts problems

    Homework Statement Hello. I am doing some problems on integration by parts and got stuck on the following problems. Any help would be appreciated. i. \int \arcsin x dx ii. \int_{0}^{1} x \ln (9+x^2) dx iii. \int x^2 \arctan x\, dx Homework Equations u\,du=uv-v\,du The Attempt at a...
  11. K

    Solving Accelerations of A Can on A Block

    woops. XD the block rotating... Thank you very much for your help!
  12. K

    Solving Accelerations of A Can on A Block

    so the block is linearly accelerating to the right with respect to the table but still rotating counter clockwise?
  13. K

    Solving Accelerations of A Can on A Block

    After much thinking, I realized that i should have considered the forces acting on each body seperately. Calling f the frictional force, we have acting on the block, F-f=M_b a_b...(1) Here Mb and ab are masses and acceleration of the block. f here is the frictional force acted by the can ON...
  14. K

    Solving Accelerations of A Can on A Block

    so it's accelerating at a=F/m?
  15. K

    Solving Accelerations of A Can on A Block

    huh, so the can is actually accelerating with respect to the table?
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