Recent content by Glenn G

Ok noted for future

TL;DR Summary: Finding the power loss in a wire of varying area - my problem is I don't know how to set up the integral Hopefully you can see in the diagram below that the area of the wire varies linearly with length. I know the equations for resistance and power loss and I can express the...

Thanks Steve, Ah so makes sense that if d is less than half a wavelength then at no point on that line between the 2 speakers can there be a point where there is complete destructive interference since they won’t ever be out of phase by half a cycle … ok if I’ve got that correct it makes sense...

Hello all, I have been working through a number of past Olympiad questions for fun. This one, though, I find very strange - even after looking at the answer i'm confused. I know when the path difference from the two speaker is lambda/2 you would get destructive interference (typical A level...

Yay, that looks great for giving the 0, pi/2 and pi relationship for the correct ‘zones’ - was Barton’s pendulae that got me thinking about this. Thanks.

Thanks Vanhees71 …. So is there a better ‘match’ of formula for the actual shape of the phase characteristics that does go from 0 to pi as W goes from 0 to infinite as in my sketch if the normal arctan isn’t appropriate ?

This is an equation I found for the delta phase lag of a driven oscillator. W is the driving angular frequency and Wo is the natural angular frequency of the driven system. Of course this is just a small part of the solution to the differential equation. Now ... 1) when W is much smaller than Wo...

Hello all, this is an adaptation of a question i saw some time ago (can't find the original now). There are two forces acting on two masses both 1kg. The masses are joined by an inextendable rope and going over a frictionless pulley of negigible mass. In blue I have written in some working out...

Was thinking about that but the bolts would be attracted so that work would be done by the magnet itself

Hi, I have read some threads on this but I still have some confusion. 1) I get that work has to be done to produce a permanent bar magnet (work to align the dipole moments to give a net field, say in a solenoid/electromagnet) so we can say that the magnet is a store of magnetic potential...

I had a number of lab steel springs (ones used in science class) - interested to see what happened when I heated and quenched - had seen a video about it becoming brittle (it did) but my question was really about how weak it became. Thanks for reply.

Thanks for the reply.

Hi group, I heated a steel spring until red hot then plunged in water quenching it. My understanding is that quenching so quickly would have an effect of the grain size such that I would expect it to be much more brittle as with small grain there is much less plastic deformation possible (as...

Sorry I meant the glancing beam starts to refract in at 41.8 degrees - if we reverse the arrows in the above diagram

Yeah, still baffled by the skimming on the surface reality. Feels like we've either got refraction away or reflection off but if you drill at the interface between refraction away and reflection don't think you can wave the 90% refracted angle away. Refracted angle is clearly approaching 90...