Recent content by dwintz02

Homework Statement Assume a rocket ship leaves the Earth in the year 2100. Castor, one of a set of identical twins born in 2080, remains on Earth to work at Mission Control, while the other twin, Pollux, travels in the rocket. Ignore the motion of the Earth relative to the fixed stars. The...

http://en.wikipedia.org/wiki/Alpha_radiation http://en.wikipedia.org/wiki/Beta_radiation http://en.wikipedia.org/wiki/Gamma_radiation A little ways down it'll say something about how each type is stopped. If anything is still hazy after you look through those websites, just ask.

Ok, first let's understand the energetics of what is going on. In your original reaction you are shooting protons at copper nuclei and this is causing a proton capture reaction. You could calculate the Q value for this reaction using masses only if the proton didn't carry kinetic energy...

Sounds like you should use the Clebsch-Gordan coefficients for adding angular momenta. But if you want to do it explicitly (as you'd probably have to do on your exam if it was a question) post the two spins you're adding and your work and we can help you along. It's easier to handle it with...

Usually it's safe (and common) to use a thin-lens approximation. I'd say the best two answers are index of refraction and curve of the lens, but thickness of the lens is technically correct also.

Initial rates works because you get your data before any significant changes in concentration occur. Why would it be disadvantageous to wait longer?

First, KE_0=PE+W_f Make sure this equation makes sense to you intuitively. The object starts with only kinetic energy and this energy is transferred to other forms of energy--potential energy and 'wasted' energy of friction. Since the skier is stopped, he/she has zero kinetic energy...

You just need another operator that has eigenvalues that are functions of m that also commutes with the Hamiltonian.

So you have: L_0+\delta L=4\pi\sigma(R_0+\delta R)^2(T_0+\delta T)^4 You will have to use a Taylor Expansion to expand the terms that can be considered very small. For example: (a+x)^4=a^4(1+\frac{x}{a})^4 \approx a^4(1+\frac{4x}{a}) This only works when \frac{x}{a} is very small...

I'm getting different eigenvectors than you because I don't know how you went about solving for yours, so I just want to check if yours are ok. Here's my method: multiplying out the your first equation and letting the components of my eigenvectors be 'a' and 'b' I get...

Right. When are L and w parallel? This one's tricky--they are parallel when the elements of the inertia tensor are diagonalized (all off diagonal elements are zero). This causes the inertia tensor to act as a 'constant' (I don't know the right word.) Check the matrix multiplication to see...

When you say Euler's equations for a rigid body with no external forces I assume you mean: (I_{2}-I_{3})\omega_{2}\omega_{3}-I_{1}{\dot{\omega_{1}}}=0 (I_{3}-I_{1})\omega_{3}\omega_{1}-I_{2}{\dot{\omega_{2}}}=0 (I_{1}-I_{2})\omega_{1}\omega_{2}-I_{3}{\dot{\omega_{3}}}=0 Try solving...

I believe Einstein just predicted it in 1905 and Millikan proved it 10 or some odd years later. He was a relatively smart guy or something.

You have the right idea for the eigenvalues. For the degeneracies, think of how many states have the eigenvalue l(l+1)hbar^2. More directly, how many m's are possible for a given l?

For a person standing on the Earth at the equator, how about: GMm/r^2 - N = m*v^2/r Sorry for the confusing post earlier, I meant mass times the centripedal acceleration. Remember the normal force (N) is still relevant here because the Earth is physically pushing the person away from the...