Recent content by element1945

Homework Statement Justify the following expretion, in spherical coordinates; delta (vector r) = (1 / r^2 * sin (theta) ) * delta(r) * delta(theta) * delta(phi) Homework Equations The Attempt at a Solution I don't know what it means... please help?

The simple case of Stoke's Theorem for a rectangle in the x-y plane. I use green's theorem because n = k. The question is... what should i choose as a vector function F? I just want to prove stoke's theorem for this case. Do i need a vector function?

Thank you very much.

U (x , y , z) = (1/2)*k*x^2 + (1/2)*k*y^2 + (1/2)*k*z^2 + C I am i correct?

ohhhhhhhh i just need to derive these equations and substitute the constants and find U (x, y, z) Thank you so much guys!

yeah i forgot the constants...but i thought i wouldn't need them...because i don't have initial conditions to solve for them. thanks

Thanks a lot, but something that i don't understand is how to choose the segments of the path... can i just evaluate the indefinite integral?

so i just integrate the components; Ux = k/2 x^2 Uy = k/2 y^2 Uz = k/2 z^2 how do i put U as a scalar function?

If F is a conservative force, written in terms of a vector: F = kx i + ky j + kz k where k is a constant, How do i find the potential energy? I know how to use partial derivatives, but I am not sure how to integrate a vector. Please Help.

i don't know how to relate the total and the released energy, and how to relate the 50% efficiency with the released energy and the global consumption... please help :(?

i forgot that the total energy of Uranium is the binding energy i think that is 1786 MeV.

The moles of 14C in the living tissue are (1.17 atoms 14C / 6.023x10^23 atoms) x 1 mol = 1.94x10^-24 mol I am correct?

do the ages that i calculate are correct?

Ok in the problem there's no data for 14C left in the sample. the only facts are the ratio in the sample: 6.1x10^-13, and the ratio of a living tissue: 1.17x10^-12. how to i calculate the 14C left in the sample? and there's the half-life...there are no other facts :(

Homework Statement What proportion of the total energy in Uranium-235 is extracted through nuclear fission? In 2001, the world electricity consumption was 13.81 trillion kWh. Assuming 50% efficiency in converting and distributing the power, and imagining that all production was nuclear...