Recent content by LordGfcd

  1. LordGfcd

    What is the continuity condition for the heat flux through a boundary?

    Assume there is a boundary separates two medium with different heat conductivity [κ][/1] and [κ][/2]. In one medium, the temperature distribution is [T][/1](r,θ,φ) and on the other medium is [T][/2](r,θ,φ). What is the relationship between [T][/1] and [T][/2] ? Is it - [κ][/1]grad [T][/1]=-...
  2. LordGfcd

    The shape of the surface of a soap film

    Ok thanks very much. It was the project of the tension on the z-axis. My solution had the same idea as Raihan's - pressure equillibrium.
  3. LordGfcd

    The shape of the surface of a soap film

    Hi. I was trying to solve the same problem you submitted. And I've read Chestermiller's solution to the problem. But I don't understand why in the post #13 there is a sqrt(1+(dr/dz)^2)) ? I would appreciate the help. Thank you.
  4. LordGfcd

    Compression of an object under it's own weight.

    Thank you very much, I was completely wrong with my argument.
  5. LordGfcd

    Compression of an object under it's own weight.

    Actually I solved this problem assuming the cube is deform before the normal force make balance with gravity. I eventually find an acceptable result (a=10cm,m=1kg,E=10^7 Pa) : 2,27 μm. But I still think my approaching is wrong because I didn't consider the normal force (action equal minus...
  6. LordGfcd

    Compression of an object under it's own weight.

    Let's first consider a cube side length a, mass m, Young's modulus of the block is E. How do we calculate the decrease of the height of the center of mass of that cube ?
  7. LordGfcd

    A fluid mechanics problem -- Shape of a falling water drop

    Oh, it's must be my fault, I totally forgot the surface tension. The original problem was just "find the mathematical description of a shape of a falling drop of water in the atmosphere" so I added some variables and data that I thought would be involved. I will take another attempt and see what...
  8. LordGfcd

    A fluid mechanics problem -- Shape of a falling water drop

    Well, there is the atmospheric pressure and the bulk modulus that determine the size of the water drop. If the velocity is constant then the dragging force should be constant too but different with each part of the water drop. The force on the x-axis will be p0.dS and the force on the y-axis is...
  9. LordGfcd

    A fluid mechanics problem -- Shape of a falling water drop

    Not yet, I'm still working on it but haven't got much progress.
  10. LordGfcd

    A fluid mechanics problem -- Shape of a falling water drop

    Hi, I was wrong about the bulk modulus definition :v It was K=-v.dP/dV. My bad :(
  11. LordGfcd

    A fluid mechanics problem -- Shape of a falling water drop

    Homework Statement A drop of water fall towards the ground with initial mass [m][/0] and radius [r][/0] (assume the initial shape of that water drop is sphere). the air resistance is F=½.ρ.A.[v][/2].C (C is the drag coefficent, A is the area that the air contact with the water drop and ρ is the...
  12. LordGfcd

    I'm newbie here, very glad to join this community

    I'm Hien Nguyen, 16. I am studying in Hanoi University of Science (not in college yet but in the high school that the university founded), Hanoi, Vietnam. My goal right now is to be in the Vietnam's Team and participate in the next International Physics Olympiad in Lithuania (IPhO 2020). In...
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