Recent content by genius2687

Homework Statement We are interested in the solution of the Schrodinger equation with positive energy E = h_^2k^2/2m for the potential V(x) = -v_0*delta(x). We take the scattering state under the form Ae^ikx+Be^-ikx for x<0, and Ce^ikx+De^-ikx for x>0 Find the scattering matrix S(k)Homework...

I know what I did now. For partial derivatives, dx/dy not= 1/(dy/dx). I falsely made that assumption.

Homework Statement Show directly that the transformation; Q=log(1/q*sinp), P=q*cotp is canonical.Homework Equations Since these equations have no time dependence, the equations are canonical if (with d denoting a partial derivative) dQ_i/dq_j = dp_j/dP_i, and dQ_i/dp_j = -dq_j/dP_i The...

A solid sphere of radius a is immersed in a vat of fluid at a temperature T_0. Heat is conducted into the sphere according to dT/dt = D(d^2T/dr^2) (d-> partial derivative btw) If the temperature at the boundary is fixed at T_0 and the initial temperature of the sphere is T_1, find the...

What exactly does that term mean? I thought it meant getting some quantity in the form of an integral, but I can't be sure.

What would be the horizontal force pushing the wedge? If the wedge was at rest, the total force on the wedge from the block would be mgcos(theta), just like the normal force that the wedge exerts on the block (Newton's 3rd law). However the wedge accelerates and even though Newton's 3rd law...

Yes but can we assume that the normal force to the wedge on the block is mgcos(theta) when we have a system where the wedge is moving? It just seems like if the wedge is accelerating then the normal force on the block will not be mgcos(theta). Almost as though we have to work with the system...

Problem: "A smooth wedge of mass M has a triangular cross section with a side inclined at an angle theta to the horizontal base. The wedge can slide without friction along a horizontal support. Placed on the side of the wedge is a mass m that can slide with no friction along the side. Find...

Thanks for the advice. I got the answer except for a factor of 1/2. Though I used delta_x*delta_p=h_bar/2 (That's the relation in my QM textbook. I've seen the 1/2 factor left out, so I think I got the right idea.)

This is a problem to a practice qualifying exam for graduate students. A series of marbles, each with mass m, is dropped from a height H directly above a line on the ground. Although a high precision dropping device is used, each marble does not land on the line. Show that the typical...

I'm looking at a question to a practice exam. It states the following. Imagine the universe is a spherical cavity at a temperature of 3K. Using this assumption, estimate the total number of photons in the universe. Notes: integral[0->infinity,{x^2dx/(e^x-1)*dx}=2.4 black body energy...