Recent content by Asrai

Thanks, that would be really helpful! I'm glad to know that I don't seem to be a complete moron though, or that I've overlooked some vital detail that will make the whole thing ridiculously easy.

Homework Statement A particle of charge q starts from rest at the origin of coordinates in a region where there is a uniform electric field of strenth E parallel to the x-axis, and a uniform magnetic field B parallel to the z-axis. Find the equations of motion, and solve them to show that...

Thank you ever so much, that was really helpful!

Ah, I caught the error, thank you. The electric field should then be E = Q/(4*Pi*Epsilon*r^2), right?

For a sin(\phi) d\phi I set the limits as 0 to Pi; for ad\theta I set the limits as 0 to 2*Pi. Integrating this and calculating the potential gives me V = Q/(8 \pi \epsilon r). Is this correct?

Okay, I suppose I can do it this way too. However, this does not solve my problem in setting up dS properly; I'm a bit stuck there. One bit should be the changing radius of all the circles going from 0 to a, but what's the other one?

Homework Statement Consider a thin spherical shell having surface charge density σ, and radius a as shown in the diagram (see attachment). Find, by integration over the sphere, the potential at a point P, a distance r fromthe centre of the sphere, for r > a. Using this result also find...

Thank you so much! I'm still not quite sure whether everything I've done is quite right, but everything makes a lot more sense now!

Maybe I'm just too thick to really get that problem, but how do you do that? I've got L = M*R*(gh)^0.5 for the angular velocity right after impact; but how do I get to the expression for angular velocity right before the impact? I know that omega' = V/R, but that's about it; if I then use L =...

Ok, so I've got that bit of the problem. It then goes on: Consider motion before and after impact and use conservation of angular momentum to show that the hoop rolls with a velocity V before impact as follows: V = beta*R*omega where beta = (2R)/(2R-h) Now, I don't even know where to...

But wouldn't the angular velocity change? In this problem, I though h to be constant, so the angular velocity would remain constant throughout the surmounting? Also, can I use conservation of energy or do I have to use torques to get to the answer?

I don't know about the clamp- that is the literal transcription of the problem as it is in my booklet (except that it then goes on about some other calculations). Nevertheless, if my calculations concering omega were correct (the omega before it left the ground), how can the omega after the...

Oh dear. I thought this problem sounded dodgy... But how do you then calculate omega, by approaching the problem using torque? What I don't understand it that it hast just the right energy to surmount the counter but still has angular velocity after arriving at the top- how can that possibly...

A heavy uniform hoop of mass M and radius R rolls in a straight line on level ground without slipping. It encounters a step of height h, where h<R perpendicular to its path. On striking the corner of the step, the hoop does not rebound and has sufficient energy to just surmount it. If the...

Thank you so much, that really helps! Wouldn't the constant of integration be omega at t=0?