Recent content by luiseduardo

Question Consider a heating system with strongly inductive characteristic and with an electronic control of temperature performed by varying the firing angle of a single-phase controlled bridge. a) Determine the value of resistance to to ensure a maximum power of 7500W if this system is powered...

Homework Statement A long conductive cylinder contains two cylindrical cavities, as shown in the diagram. Find the magnetic field produced at point P just above the surface of the cylinder, the total current in the I and uniform current density over its section. Homework Equations...

Thanks man.

Homework Statement Two converging lenses of the same focal length f are separated by distance 2f. The axis of the second lens is inclined at angle θ = 60º with respect to the axis of the first lens. A parallel paraxial beam of light is incident from left side of the lens. Then: (A)...

Thank you very much TSny ! I found the electric field created by hemisphere is σ/4.e0, so, my problem is 1/4 of a hemisphere, so, axis z = y = x = σ/16.e0, now, using pitagoras, we can find the answer ! :)

Thanks, but could you be more specific? Because how to calculate this component without using spherical coordinates.. I'm confused..

Hum... If we draw a cube over the sphere of picture? We can calculated something?

Using cartesian coordinates?

But, this problem is from a middle school book, so don't think spherical coordinate is the unique solution. Did anyone knows other way to solve this problem ?

The flux in total sphere is x, so flux now is x/8.. No?

Homework Statement Calculate the intensity of the electric field (in the origin of cartesian axes) created by 1/8 of a certain sphere charged with density of charge equal σ. Answer: \frac{{\sigma \sqrt 3 }}{{16{\varepsilon _0}}} Homework Equations E = KQ/R² Flux = Q/ε E.A = Q/ε The...

Homework Statement The ball 1 can be charged to a certain charge Q by a generator. After that, through contact with the ball 2, the first ball can transfer to second ball part of its charge. After the first contact, the ball 2 has a charge q. Before the contact, the ball 2 was neutral. What...

Thank you very much Chestermiller !

Well, chestermiller, I tried what you suggested, please, correct me: a) Fel1 = K.Δx1 b) Fel2 = K.(Δx2-Δx1) c) Fel1 = Fel2 + T d) Δx1 = Δx2/3 + T/3K e) Fel2 = K(Δx2/3 - 2T/3K) f) mg - T -Fel2 = m.a I'm a bit confused :|

Homework Statement Find the period of low-amplitude vertical vibrations of the system shown. The mass of the block is m. The pulley hangs from the ceiling on a spring with a force constant k. The block hangs from an ideal string...