1. T

    Capstan Equation

    I need help please, as this math is beyond me For capstan , bollard frictions. I even have trusted document that has let me make sense and understand many things of knots and bollard frictions. . Jrre.org/att_frict.pdf gives .25 coefficient for nylon rope on aluminum pipe for brake force...
  2. N

    Euler's equation and integration help!

    Hey guys, So I'm going to give you two links to imgur, one is the question and the other the answer. I know how he gets the answer, i can get the answer myself but i have a question.. Do we ALWAYS integrate Euler's equation to use it? OR is this a special case where it gets integrated...
  3. P

    The Supposedly Stochastic Allen-Cahn Diffusion Equation

    The allen cahn equation describes the stochastic diffusion of different substances in alloys. If thats the case, how can there be an equation to describe this process? This seems paradoxical. Thanks for the help.
  4. K

    Equation for chemical potential of pure substance. Unsure why this derives as it does

    Hello, I am new to this. I have attached a screenshot from a journal article which talks about deriving Fick's first law. My calculus is a little rusty, and I don't understand how equation 5 is derived from equation 4. I'd have a go, but I have little to offer. All I have to offer is...
  5. G


    in attachment
  6. N

    Schroedinger's equation

    I am trying to understand, why did Schroedinger choose to write the total energy, and then multiply with psi and then insert the wave function? What does the total energy which is potential energy plus kinetic energy has to do with subatomic particles and waves?
  7. J

    Show that psi(-x) is a solution with the same eigenvalue as psi(x)

    I have been given the assignment to show that ψ(-x) is another solution with the same energy eigenvalue as ψ(x), given that the potential is even around x=0. The solutions are one-dimensional. I have tried to get my head around it but I am not sure what to look for. My idea would be to divide...
  8. S

    Calculating Mixture Critical Temperature and Pressure using Equation of State?

    Hello Everyone, I am trying to calculate critical Temperature and Pressure of binary and ternary mixtures using equation of state. In particular, I am using Peng-Robinson Equation of State. I combined this with Van-der Waals critical criterion to get my result, but am way off experimental data...
  9. W

    Bernoulli equation

    I am confused about the application of Bernoulli's equation in aerodynamics: p0+1/2rho v^2=constant. Strictly speaking this equation is only valid for incompressible fluids without viscosity. So possibly for water, but not for an ideal gas like air. But I find this equation used...
  10. R

    How to solve this equation for tidal correction

    Hello everyone, I had been trying for days how to solve the following equation in Spreadsheet: using the dataset below: I am getting frustrated of myself for being so hard to learn. i hope somebody can help me get through this. thank you.
  11. Q

    Inverse Equation Possibilites

    3) Discuss the meaning of the following possibilities when you are solving the inverse kinematics equation of a robot analytically. (a) The solution for an angle is a complex/imaginary number. (b) You don’t get an equation for one of the angles. (c) The only equation you get for an angle at...
  12. G

    Exact thermodynamic equation of state

    Dear all, I am using molecular dynamics to calculate energy for ionic liquid. In the article that is proposed equation of state that I want to use, the author would call the energy in the following formula(u) conformational(potential energy): (du/dv)T + T(dp/dT)V = ptot But the other article...
  13. F

    Diffusion equation

    Hello! I'm a physics student and i have a problem i can't solve. I was wondering if there is anyone here who would be willing to help me solve this? House: a room (see attachment) has perfectly isolated walls, except the two windows where a convective heat exchange takes place (with the...
  14. G

    What causes rotation in the Navier-Stokes Equation?

    It is known that rotation in the flow results from the viscous terms in the Navier-Stokes (N-S) equation. However, when deriving the N-S equation from the general principle of linear momentum in Continuum Mechanics, we use the constitutive relation for isotropic Newtonian fluids which states...
  15. C

    equation of motion

    Could someone explain equation 2? (the part with the red frame) Thank you
  16. D

    the wave equation

    The wave equation: d²l/dx² = (1/k²)(d²l/dt²) Can you give me, please, a clear and intuitive explanation of the equation. For dummies. t is for time. x is probably for distance? But what does l mean? k is constant and it represents the propagation... but i can't grasp the whole idea...
  17. C

    Integration of heat transfer rate equation

    Hi everyone, I am trying to do an analysis of a steam pipeline to compare the use of steam to warm up a pipeline after shutdown versus other methods (heat strips). The one thing I am trying to figure out is the units for the integration of the heat transfer rate equation which is...
  18. D

    what does the capital L stand for in this equation?

    what does the capital L stand for in this equation?
  19. D

    Nondimensionalization of diffusion equation

    Hi, I have some difficulty to solve a nondimensionalization problem and wondered if someone could help me out. Here it is : we let a dye diffuses into an environment of dimension L. We inject that dye into a box by one face, at t = 0 on x = 0. The linear density c follows that equation ...
  20. K

    Is there something fishy about the wave equation?

    Been watching some youtube videos about the derivation of the PDE wave equation Uxx = c^2*Utt ck-r_qmNNG0 LWKmcRzN5Bo It seems to me they made a lot of unrealistic assumptions when deriving it, namely: Vibration amplitudes are small The tension in the wave is the same everywhere Vertical...