Recent content by aguycalledwil

Thanks for the responses, these have been more than helpful!

Hi everyone, I'm having a little difficulty trying to calculate the self-energy of a uniformly charged sphere of radius a. That is, the work done in assembling such a distribution of charge. It is to my understanding that 0.5*integral(ρ*ø(r)dV) should produce the answer, with ρ being...

Thanks very much, that makes sense to me! It's been bugging me for ages now, glad to get that cleared up. Thanks!

Not as far as I know.. I thought GRBs were short-lived bursts of gamma radiation as a result of a star's collapse into an ordinary black hole, which occur frequently all over the universe, whilst a quasar is an ancient supermassive black hole that emits intense radio waves. It's to my...

Okay, so this may be a little bit of a trivial question, but I've read conflicting information and found myself confused as a result. I've read from several sources (wikipedia, books) that GRB's are the most luminous events known to occur in our universe. However, I've also read that...

Thanks guys, got it!

I'm trying to differentiate 2^(x^2), but I'm getting a factor of two out and can't figure out why. I approached the question as follows.. y=2^(x^2) , so y=(2^x)^x u=2^x y=u^x du/dx = (2^x)ln2 dy/du = xu^(x-1) = x(2^x)^(x-1) = x(2)^((x^2)-x) So dy/dx =...

Ah of course! Thanks so much, that really helps.

A fairground ride ends with the car moving up a ramp at a slope of 30 degrees. Given that the deceleration of the car is 4.905 m/s, and that the car enters the bottom of the ramp at 18 m/s, calculate the minimum length of the ramp for the car to stop before it reaches the end. It seems if I...

Well, I took my half solution to class today, and it turned out I was fairly close. There is in fact an answer, it is 4 km and 120 ohms. The formula I should have used for parallel resistors is ∑R = Sum of resistors/Product of resistors. Using this, the maths becomes a lot easier.. Thanks...

Yeah, I'm 100%. I also got a negative answer at one point but assumed it to be wrong. This is an extension question so it's meant to be hard but I'm starting to wonder if it's possible..

Homework Statement A distant telephone, whose resistance is 300 ohms, is connected to the exchange 10km away by a pair of wires whose resistance singly is 50 ohms/km. A twig falls across the wires at a certain point producing the effect of a resistance, R, between the wires at that point...

Aah, I guess I underestimated the effects of the relativity of simultaneity, but of course it makes sense that at .75c the explosion would have happened before the train even passed the observer. Thank you very much, that seems to have cleared everything up for me! I've been confused about...

Okay.. I think I just about get it, albeit in a very blurred way. So using the time dilation formula will tell me how many seconds pass on the clock C from the reference frame of the observer, whilst the Lorentz transformation formula I used tells me what clock C will read when the explosion...

Thanks again, Jesse for your more than helpful discussion. Yeah my bad, I did mean for the formula to be (t - (vx/c^2)), I just wasn't thinking when I wrote it haha. I get a little confused when you introduce the relativity of simultaneity. As an isolated concept I understand it but put...