Recent content by stroustroup

Oh I see. Because of the point charge disturbing the conductor, the distribution of charges has to be non-symmetric if we want the electric field in the conductor to be zero, that makes sense. So this also explains why the field is zero below the plane, since a finite charge of +Q is spread out...

I don't see why this should be true. Is it because the electric field inside the conductor is zero? But why wouldn't the positive charges be distributed symmetrically to the negative charges?

This question seems to come up often, but I cannot find a satisfying explanation. There is a point charge +Q some distance above an infinite conducting plane. Supposedly, the electric field below the plane must be zero. I have trouble understanding why this is true. The total charge on the...

The only force really considered in classical mechanics is gravity. And yet, we often have problems involving collisions and friction, which are intrinsically electrical phenomena, and thus outside the scope of classical mechanics. We have laws such as conservation of momentum which is used for...

Wikipedia claims that the Chandler wobble (a deviation of the angular velocity vector of the Earth with respect to the principal axis) is a nutation (see http://en.wikipedia.org/wiki/Chandler_wobble). But suppose we choose our inertial frame so that the Earth's angular momentum points in the +z...

Thank you for the help. I had forgotten about this thread for a while, but after reading it I realize I forgot to divide the voltage by s when moving into the s-domain. The time-domain voltage would be 4V * H(t) (step function) and so the Laplace transform is 4 / s. The capacitor explanation...

Homework Statement The switches have been in their initial positions for a long time, and switch to the other position at time t = 0s. Find v_0(t) for all t > 0. Homework Equations See the attached image for the circuit (I had to draw it because I don't have access to the original image...

From what I understand, laptops have a wireless adapter that sends radio signals at a specific frequency to connect to a wifi router. My guess is that the wireless adapter is some sort of radio wave emitter/reciever, and could in theory be used for any other purpose besides connecting to a...

Well... this is much simpler than I expected :redface: I guess I should have thought a bit more before posting that... I was convinced this would involve some advanced math and big time complexity.

Is there an algorithm which, given n, returns an integer x such that 2 has order n modulo x (i.e, 2^n = 1 mod x and n is the smallest positive solution)? Is there any such algorithm which runs faster than factoring n?

In our differential equations class, we learned about Ordinary and Regular Singular Points of a differential equation. We learned how to solve these equations with power series using the Frobenius method. I was wondering what happens when there is an irregular singular point, like...

I am trying to solve past Putnam Competition problems. I think I have a proof for Problem A5 of the 2010 exam. Here is the set of all problems: http://inside.mines.edu/~dlarue/putnam/exams/2010.pdf The solution given required three lemmas to prove, so I wonder whether my proof is flawed (it...

Well, in this particular case when the bullet hits the block horizontally, the initial moment of the system about the center of mass is 0 since the bullet moves towards the block's center. The angular impulse is 0, since there are no net torque. So after the collision, the angular momentum must...

I have an argument with classmates about the trajectory that the block will have (circle, ellipse, something else...). The configuration is similar to this image. http://minireference.com/_media/physics/momentum-bullet-speed-block.jpg?w=400 Initially, the block will move horizontally...