Recent content by Brilliant

Homework Statement Consider this wave packet: \Psi(x)=A exp \left[\frac{i(p + \Delta p)x}{\hbar}\right] + A exp \left[\frac{i(p - \Delta p)x}{\hbar}\right] (from a previous problem) This time-dependent form of the packet is: \Psi(x)=A exp \left[\frac{i(p_{1}x-E_{1}t)}{\hbar}\right] + A exp...

Homework Statement If \sum_{n=0}^{\infty} c_{n}4^n is convergent, does it follow that the following series are convergent? a) \sum_{n=0}^{\infty} c_{n}(-2)^n b) \sum_{n=0}^{\infty} c_{n}(-4)^n Homework Equations The Power Series: \sum_{n=0}^{\infty} c_{n}(x - a)^n The...

Thank you very much for your reply. That makes the problem MUCH simpler. I had actually been stumped before about how current was even able to flow across a capacitor at all, then I read about how charge collecting on one plate would cause charge to move off the opposing plate, causing a...

Homework Statement Homework Equations Q=CV The Attempt at a Solution For part A, I've tried working out the algebra, with the assumptions that V1 + V2 = V and Q1 + Q2 = Q Basically, I solved Q by finding the equivalent capacitance, then said Q1=C1*V1 and Q2=C2*V2 Then by my...

Homework Statement Find the voltage at Va. Homework Equations Ohm's Law, Current Divider, etc The Attempt at a Solution This is the almost identical to the cookie cutter voltage divider, except that there is a resistor on the output. I'm curious if current would even flow...

Yeah that makes sense to me. If the plastic ball has a higher velocity, then it will have more drag. I also think that even if they were moving at the same velocity, and therefor experiencing the same force of drag, the plastic ball will be more affected because of its lesser mass. The drag...

Yes. And the FM=-mg is an action reaction pair which is Newton's 3rd Law. Also just a tip from my experience. I can tell by the way you worded the question: "Calculate then...put in" that you are going to solve for it then move on. Many times it's better to just work with the symbols until...

OK, well you have the correct equation, but you seem to lack understanding about Newtons's 2nd Law. Which ultimately yields F=ma. Secondly it's important to remember that forces and accelerations are vector quantities. Now the problem isn't very clear, but I'm nearly positive the 5N is...

Well, we have learned all of the concepts, it's just I was having trouble putting all that together. And it seems a bit more in-depth than most other multiple choice problems. I appreciate the help though.

Wow I see the light, though I feel like I should already know this. And you're ignoring the shell of mass that has a radius grater than the falling objects radius as it falls, and only using the sphere on which it sits, basically. I guess all of the mass in the outer shell exerts a net force...

OK starting to understand, but there is something I'm missing. I don't understand what grad U = F means, and also where the R cubed came from. I think the two are probably related. Maybe something with Fxr = -U? But I still don't see where R cubed will come from. Probably some calculus? I...

This is from an old AP test, and it's a multiple choice question, so I don't know why it's giving me so much hell, but here it goes: Homework Statement Suppose that a hole is drilled through the center of the Earth to the other side along its axis. A small object of mass m is dropped from...

I dunno, you're getting it, but why multiply by 4, that means it's going to complete for cycles. Min|----------*----------|Max equlib It's staring at the equlib position, and one whole period T would be ---->-----> <---<---*----<----<...

You've practically got it. You're just confusing max amplitude with max velocity. Yes, it is at max velocity when it gets shot (equilibrium), but it's T/4 from the max amplitude because it's traveling in the positive x direction.

Yes, you're right. I do this all the time. Thank you very much! Sometimes I just need to be slapped.