- #1

- 471

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http://img148.imageshack.us/img148/7599/981718254748dd2.png [Broken]

My work, my answers are wrong obviously.

18. [tex]U_{E}=\frac{kq1q2}{d}[/tex] -- I substituted the electric force with the work equation to get this.

25. Q=mL, Q=mcT . I combined these to get mL=mcT, stuck from there.

47. F=q(v x B), v=F/qB, F=mv^2/r

I combined these equations to get: mv/r=qB and solved for v and I then I just guessed.

48. Why is the answer D?? I know that it has something to do with lenz's law but I only know how to apply that law for magnets moving with either North or South pole. (If a north pole of a magnet moves towards the wire the induced current is counter clockwise right? If the south pole moves into the wire it is clock wise?)-- Is this right?

Thanks for your help guys! =]

My work, my answers are wrong obviously.

18. [tex]U_{E}=\frac{kq1q2}{d}[/tex] -- I substituted the electric force with the work equation to get this.

25. Q=mL, Q=mcT . I combined these to get mL=mcT, stuck from there.

47. F=q(v x B), v=F/qB, F=mv^2/r

I combined these equations to get: mv/r=qB and solved for v and I then I just guessed.

48. Why is the answer D?? I know that it has something to do with lenz's law but I only know how to apply that law for magnets moving with either North or South pole. (If a north pole of a magnet moves towards the wire the induced current is counter clockwise right? If the south pole moves into the wire it is clock wise?)-- Is this right?

Thanks for your help guys! =]

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