Recent content by WalterContrata

Resultant OK, the desired result is flying straight towards Indianapolis. Can you make a vector diagram showing this result as the sum of other things?

Darn. He didn't apply Virial therom , but did he state conditions under which it is true? I don't think it is good for all systems. (But I'll be glad if someone can teach me otherwise.) Sorry to be unclear. In writing "How does it work...?", I'm referring to the limit that you wanted to...

Don't mention it -- I thought it was a typo, but wanted to make sure.

I hope that wiser and more knowledgeable heads than mine will return to correct the following, but Does Gasiorowicz explain the virial theorem in his text? What kind of systems does it apply to? Maybe it is hard to prove your limit in the general case. How does it work if you think about...

If I were doing it, I would try to stay consistent with the teacher's style. That will minimize the probability of confusion in class. However, it is good to know there are other ways of writing these things, so that you can read textbooks with different notation, and pick a suitable style...

DB, Good going. I got the same answer, except in the last sig. fig.'s. As for how to write it, how does your teacher usually write these vectors? I often saw coordinates in brackets or parentheses like (3,4) or magnitudes with unit vectors, like 3i + 4j.

Great. The Tau_n in the formula for mu_n should be the average time between scatterings for an electron. What is the dominant scattering mechanism? Does it involve the recombination levels? Carrier lifetime usually refers to something different. Suppose that there is a hole in this...

OK, how did you convert the polar coordinates to rectangular?

Please Clarify I take it that the densities are in cm^-3? When we talk about semiconductors, I think that "impurity" often refers to donors and acceptors. Is it 10^16 donor impurities / cm^-3? And you have of second impurity that results in a 10^10 deep levels/cm, and this level...

...Strange that there is nothing to do with the vector B.

I think that you are on the right track. If asked to simplify the expression without further instructions, I would do as you have done. Please check your conversion to rectangular form, I think some of the coordinates are interchanged.

If you understand the problem of the trolley with constant velocity, then you are well started. In that case, the acceleration is zero, and therefore the sum of forces in any direction must be zero. In particular, the sum of forces along the line of motion must be zero. If the object is...

Fred, Thanks again. I'll check out the links.

That's a good question. Are we allowed to assume that V is proportional to x^-1 or higher power, and V -> 0 as x -> infinity?

Good approach, but I think you are a little off. If the ladder is not moving, the sum of the forces in any direction must be zero. In particular, the sum of the forces in the y direction must be zero. Which forces have components in the y direction, and what are their magnitudes? Hope this...