Can anyone figure out how to calculate the mag (0.171) of the example prob on page 7 on notes set 8? I would think you would do (2/32) + (3/26), but that is 0.177. Thanks.

2/26/2007 6:52:40 PM

Nevermind...got it.

[Edited on February 26, 2007 at 9:37 PM. Reason : ]

2/26/2007 9:23:23 PM

[Edited on February 26, 2007 at 9:39 PM. Reason : nm]

2/26/2007 9:39:30 PM

New question...having trouble with 8-10. Since F=qE, E is zero since Q3 doesn't move. If Emag of the system is zero, that only leaves us with 1 equation and two unknown variables (x,y). Where does the other equation come from?

[Edited on February 26, 2007 at 9:56 PM. Reason : ]

[Edited on February 26, 2007 at 9:57 PM. Reason : ]

2/26/2007 9:53:18 PM

Think about where Q3 has to be in relation to Q1 and Q2.

2/26/2007 10:05:11 PM

Thanks.

2/26/2007 10:09:40 PM

I can't get my calculator or Matlab to solve this large of a system of equations. Any advice?

2/26/2007 11:20:10 PM

^ learn how to use Matlab correctly?

2/27/2007 12:54:42 AM

Yeah, you may want to look at your problem again...

There are two equations and two unknowns. Substitute one equation into the other, simplify, and you should eventually come out with a second-order polynomial. Find the roots and determine which of the two roots is a valid answer. Use the root and one of the equations to find the other unknown.

This can be done by hand in less time than it would take to put it into your calculator or Matlab.

2/27/2007 8:24:46 AM

in matlab, just use \ division:

define your coefficient matrix A, your solution vector b, and then just do A\b.

instant profit

2/27/2007 10:14:26 AM