# Recent content by Waldheri

1. ### Navier Stokes Equation Derivation and Inertial Forces

Not sure if I understand exactly what you mean, but if a volume element is size b*dx*dy (= dV), then mass m = rho*dV. Acceleration is nothing but the change in velocity, so ax = du/dx. A force Fx = m*ax = b*dx*dy*du/dx. Perhaps it is good to keep in mind that the Navier-Stokes equation is...
2. ### Fourier transform

Substitute the definition of g(t) in the Fourier integral and try putting the exponentials together. You'll probably see it then. ;-)
3. ### Correct differentiation identity? (tensors, vectors)

Hello, I'm working on some problems and I want to pose the following, though I am not completely sure it is correct. Can somebody point me to some sources on this? I have tried googling myself, but I only found differentiation identities with either just vectors and scalars on the on hand, or...
4. ### Cayley Hamilton Theorem

Hey matqkks, I have come across the Cayley-Hamilton theorem in a college rheology class. Rheology is basically the study of material behaviour, and so rheologists look for equations that can describe materials. Elastic solids are simple in this regard, and can be with a linear relationship...