Recent content by Sami Lakka

I read interesting article regarding Halbach arrays and magnetic levitation (see [PLAIN]www.lmco.cn/data/assets/9197.pdf[/URL]). In the article (see equation 1) the author states that the voltage generated by moving magnet over rectangular coil is V= L*dI/dt + RI = \omega \Phi cos(\omega t)...

Homework Statement What is the equivalent capacitance of the arrangement shown in figure. (Answer is C1) Homework Equations Cparallel = C1+C2+...Cn Cseries = 1/(1/C1+1/C2+...+1/Cn) The Attempt at a Solution

Ok, now I think I got it. I should use Stokes' theorem with F=1 (scalar). What bothered me was that I was all the time looking at the cross product in curl which is not defined for scalars. Of course the cross product is only a notation, not actual vector cross product.

Yes, sorry about the notation, it is direct copy from the book that I'm studying. t is a unit vector with components (dx/ds, dy/ds, dz/ds) so after the multiplication the integral is taken from vector (dx, dy, dz)

Homework Statement Use Stokes' theorem to show that \oint\ \hat{t}*ds = 0 Integration is done closed curve C and \hat{t} is a unit tangent vector to the curve C Homework Equations Stokes' theorem \oint F* \hat{t}*ds = \int\int \hat{n}*curl(F)*ds The Attempt at a Solution Ok...

Here is the problem statement from word to word. The problem is in Div, Grad, Curl and all that, p. 55, problem II-11 a) Use Gauss' law and symmetry to find the electrostatic field as a function of position for an infinite uniform plane of charge. Let the charge lie in the yz-plane and denote...

Homework Statement Use Gauss' law and symmetry to find electrostatic as a function of position for an infinite plane of charge. Let the charge lie in the yz-plane and denote the charge per unit area by \rho=\alpha*e^{-abs(x/b)} Homework Equations Q=triple integral of density The Attempt at...

Homework Statement The distribution of mass on the hemispherical shell z=(R2 - x2 -y2)1/2 is given by \sigma= (\sigma0/R2)*(x2+y2) where \sigma0 is constant. Find an expression in terms of \sigma0 and R for the total mass of the shell Homework Equations The mass is given by double...

Hi Natural frequency of spring is fn = 1/(2*pi) * sqrt(k/m), where k = spring constant and m is the mass. Ok, so I have a spiral spring which means that spring is coiled couple of times. Its spring constant is (according to Hartog's Mech. Vibrations), k = E*I/l, E=Elastic Modulus, I = Inertia...