2 Physics questions

Trying to finish up all my physics homework and I'm stuck on these two questions.  I don't necessarily want someone to just post the answers I'd really like to just find out how to solve them...

First question: A figure in my book shows a metallic block, with its faces parallel to coordinate axes.  The block is in a uniform magnetic field of magnitude 0.020T.  One edge length of the block is 25cm.  The block is moved at 3.0 m/s parallel to each axis in turn, and the resulting potential difference V that appears across the block is measured.  With the motion parallel to the y axis, V = 12mV; with the motion parallel to the z axis, V = 18mV; with the motion parallel to the x axis, V = 0.  What are the block lengths (a) dx, (b) dy, and (c) dz?  With dx, dy, and dz being the edge lengths.

Second question:  A certain commercial mass spectrometer is used to seperate uranium ions of mass 3.92 x 10^(-25) kg and charge 3.20 x 10^(-19) C from related species.  The ions are accelerated through a potential difference of 100 kV and then pass into a uniform magnetic field, where they are bent in a path of radius 1.00m.  After traveling through 180 degrees and passing through a slit of width 1.00mm and height 1.00cm, they are collected in a cup.  (a) What is the magnitude of the perpendicular magnetic field in the separator?  If the machine is used to separate out 100mg of material per hour, calculate (b) the current of the desired ions in the machine and (c) the thermal energy produced in the cup in 1.00h.

wut

you fail, wut is not an answer...man this shit is due 2moro morning....i hate physics

lol school, just learn a trade

i am learning a trade, it's called electrical engineering and it's what is going to earn me 60K starting salary when I graduate...that is if the economy doesn't implode before then

>>1
1) The metal block is a collection of positive and negative charges that you're forcing to move in a magnetic field, which is sort of like the hall effect.  The motion causes the charges to separate (mostly negative charges), which then set up an electric field to oppose further change.  If you don't know which way the B field is pointing, you're kinda screwed.  As for the edge lengths, you're probably going to have to do some brute forcing.

2)
+ charges accelerated by E field -> you know how fast they are -> you know how much it bends in a B field. b) change mass/hr -> charge/s, given the particle's mass/charge ratio c) I assume all of the particle's kinetic energy gets changed to thermal energy in the cup?

>>5
I've never heard of an electrical engineer refer to their job as a "trade" (university =/= trade school); they refer to it as a profession.  You're a fruitcake.  If you're a good EE, you can earn well over 100K.  However, given your fail here, I don't expect you to progress much further than MOSFETs.  Enjoy your imploded economy/lack of a job.

>>6
Re 1).... you're retarded... 'brute forcing'... That was a joke, right?

OP - get a textbook, presumably you have some recommended. I'm not gonna look this shit up for you.

>>7
I just noticed
with the motion parallel to the x axis, V = 0
That forces the B field to be in the x direction, so no brute forcing is necessary (which also means dx = 25cm).

Otherwise... it was going to get really hairy.

Im gonna kill 4tran hes a chink.

>>9
Death threats now... time to fag this board up even more.