Recent content by greg_rack

Thank you @Lnewqban for your answer! Another doubt I have regarding to this is: what if I instead took moments about some point other than the SC? If we don't have torque in the cross section, does this mean that about any point the moments originating from the shear flow distribution must add...

Thank you for sharing this! Then here, quoting the problem statement: "You may assume the internal loads act at the centroid." Which means we can approximate the SC to be located @ C, as internal loads do not cause twisting by definition... correct? So in this case, for figuring out whether we...

As you can see from the picture, the cross section to analyze is idealized and the boom areas resulting from this are given. For POINT A) all I did was: for determining the shear forces, integrating the shear flows over the sides to compute the vertical and horizontal contribution of each side...

Here is the diagram of the cs: As a premise I must say that this topic(shear center and shear flow distributions) is still very hectic in my mind; I aim to clarify it a bit by asking you guys this :) So, in order to identify the SC location, I must compute at what distance a point shear force...

Howdy guys, Say we have been given the four thin-walled cross sections below loaded in pure torsion, where the material in black, titanium, has E=100GPa and the one grey one, aluminum, E=75GPa(no clue why Es are given, as I would have expected the shear modulus, G... maybe it is expected to use...

Could someone check whether my proof for this simple theorem is correct? I get to the result, but with the feeling of having done something very wrong :) $$\mathcal{L} \{f(ct)\}=\int_{0}^{\infty}e^{-st}f(ct)dt \ \rightarrow ct=u, \ dt=\frac{1}{c}du, \ \mathcal{L}...

Yeah actually, none I would say. It is still a periodic function, so no big deal

Oh yeah you are right, but this then would lead to a final minus in front of the whole expression for Q(t), right? Performing all the calculations, after correctly integrating the e term, leads me to: $$Q(t)=\frac{-V_0}{\sqrt{(\omega R)^2+(\omega ^2L-1/C)^2}}e^{j(\omega t -\phi)}$$ ... unless I...

But there, the ##e^{j\phi}## factor from polar form is at the numerator, not at the denominator... no?

@Delta2 @TSny and everyone else, I will put here also another problem for which I had a very similar issue with phase signs, and for which what was pointed out in #4 doesn't seem to apply. (sorry if I have attached the image directly, but I think it'd be much clearer) So what happened here was...

Ok wow, that is indeed a good point, super cool! Actually, I would have intuitively said that here the rotation should be CCW because an inductor is present in the circuit... but now this argument seems a bit weak. Is it really all there's to it? And by the way yes, since -whatever the reason-...

Hello guys, LRC circuits with an AC source are having the best over me... had some confusion in class with respect to which method is best using(phasors diagram, reactances or complex impedances) which I am trying to desperately sort out before my exam; here I will show you my best attempt on...

Thank you guys, I had indeed got the k hat component of the del cross F wrong! It's cool now

From Stokes' theorem: ##\int_{C}^{}\vec F\cdot d\vec r=\iint_{S}^{}curl\vec F\cdot d\vec S=\iint_{D}^{}curl\vec F\cdot(\vec r_u \times \vec r_v)dA ## To get to the latter surface integral, I started by parametrizing the triangular surface in ##uv## coordinates as: $$\vec r=<1-u-v,u,v>, 0\leq...

Ohhh, crap, I'm sorry for making so much confusion! To try and clarify things up then, Stokes' th. relates the circulation around a boundary curve to the surface integral of the circulation of the vector field(true?) of interest; what we did here was arrive to "standard" scalar surface...