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  1. J

    Energy density

    Well the way it works is my professor goes over this packet of problems (including this one) the day before the exam and leaves us to figure out the questions we got wrong on our own. And there's 165 questions in this packet. It's not a very ideal situation. If I get something wrong, it's not...
  2. J

    Energy density

    The problem doesn't say the distance between the plates.
  3. J

    Energy density

    My answer isn't even one of the multiple choices?
  4. J

    Energy density

    The new answer I get is 508475 instead of 5085. I feel like I may be using a wrong equation or something? My teacher didn't really lecture on energy density at all so I'm a bit uncertain.
  5. J

    Energy density

    Homework Statement Two large non-conducting plates of surface area A=.025m^2 carry equal but opposite charges Q = 75microC. What is the energy density of the electric field between the two plates. Homework Equations I wrote the equations on my attempt. This was a multiple choice problem...
  6. J

    Current is equaling zero?

    Thanks everyone for the help! I learned a lot!
  7. J

    Current is equaling zero?

    So I wrote 3 independent equations for each loop, and the summed up the currents. Would this be correct? You explanation made a tone of sense.
  8. J

    Current is equaling zero?

    What if I wasn't given those two equations? Would I just solve it with the 5 equations I made up?
  9. J

    Current is equaling zero?

    So I didn't get the answer right or I did? Because the 5 equations I used, 2 of them are KCL and 3 are KVL? Assuming I'm wrong, the first thing I would do is write the 2 KCL equations which are: The next step you say is to solve for the node voltages? This is where I start to get confused...
  10. J

    Current is equaling zero?

    I'm very sorry! Yes, the post in #7 makes sense to me.. I added in the top two equations and now I'm getting an answer. How does this look? When I solve the the equation in post #7, i get the I2 that I got in my system of equations. So I guess my answer is right? If it is, I'm still a...
  11. J

    Current is equaling zero?

    If my 5 equations are fine as you said, then shouldn't I1-I5 be correct values? I think my problem is over the confusion of Va1 and Va2. Should I have factored these into my equations? I though Va1 and Va2 was just specified so I can't find the potential difference at those points in part 1...
  12. J

    Current is equaling zero?

    So my equations would be How does the Va1 and Va2 play into the equations? Do they count in as batteries? And I'm confused why the loops I picked won't work?
  13. J

    Current is equaling zero?

    Doesn't the whole big loop around count? Making it 4 loops? And I don't know how to write the KCL equations? Thanks for the reply!
  14. J

    Current is equaling zero?

    I haven't tried calculating them by hand.. Didn't I write the KCL equations as a sum equal to 0? I feel like I have a sign error somewhere..
  15. J

    Current is equaling zero?

    Homework Statement Homework Equations Kirchhoff's laws and I = V/R The Attempt at a Solution I asked a question recently about a Kirchhoff's law problem and I received a lot of great help and I feel I better understand it. Or so I thought. This is my attempt at the problem. I don't...
  16. J

    Engineering Basic resister circuit with two batteries

    Thankyou everyone for all the help! I was able to get the right answer and check it in class! Thanks a ton everyone!
  17. J

    Engineering Basic resister circuit with two batteries

    I'm not sure how to write the equations. Normally I would write the equation according to the path the electrons would flow, but since there's two batteries I'm not sure where things start and end and what flows against what. Sorry, I'm just having a little trouble getting this.
  18. J

    Engineering Basic resister circuit with two batteries

    So would the currents be 12V + 9V - I8 - I7 12V - 4I - 7I 9V - 4I - 8I ?
  19. J

    Engineering Basic resister circuit with two batteries

    Ok, apparently I don't know KVL as well as I thought. How would you divide up this problem? Is there ever a point where you would include both batteries in a loop "equation"?
  20. J

    Engineering Basic resister circuit with two batteries

    I read through the link you posted. So I would have to calculate the current for each battery, and then add them together? Would it be like separating the problem into two different problems, each with one of the two batteries? Maybe if you could get me started it would help?
  21. J

    Engineering Basic resister circuit with two batteries

    We discussed that total voltage is zero and current out is equal to current in.
  22. J

    Engineering Basic resister circuit with two batteries

    Homework Statement https://i.gyazo.com/ec36f9345b56810598a5b2cebc62aeb7.png Determine the current in the 7ohm, 8ohm, and 4ohm resister. Homework Equations The series/parallel equations for equivalent resisters. and V=RI. The Attempt at a Solution I'm normally pretty good with these circuit...
  23. J

    Finding flux from cube

    I get that the flux goes through the j hat direction, so you take (3*2) = 6 and then multiply it by the area (2*2) and get 24. But my teacher wants us to solve this using a double integral in math cad for bonus points. I've never done double integrals so I just need an example or someone to do...
  24. J

    Finding flux from cube

    j? I'm not searching for someone to do the problem for me, but I'm pressed for time as we were given this extra credit assignment today, so if you could just solve this and explain the steps you took, I would really appreciate it. The only reason I am asking is because of my time constraint.
  25. J

    Finding flux from cube

    Would the normal vector be flux? I'm not sure.
  26. J

    Finding flux from cube

    I edited the original post. Sorry, I miss typed! It is at (2,2,2). The definition of flux is the integral of electric field doted with area. What am I doing wrong in mathcad?
  27. J

    Finding flux from cube

    Homework Statement Consider an electric field E = 2x i - 3y j. The coordinate x and y are measured in meters and the electric field is in N/C. What is the magnitude of the flux of this field through a square whose corners are located at (x,y,z) = (0,2,0), (2,2,0), (2,2,2), (0,2,2)? Homework...
  28. J

    Confused about electric potential and electric field

    Well that was a silly mistake on my part. Thanks for the clarification. Could you explain this vector gradient thing a little bit more? Our professor completely brushed over it because most the class has only taken Calc 2 and doesn't know about partials yet, which is the boat I am in. I...
  29. J

    Confused about electric potential and electric field

    Also why is the equation for potential energy = kq1q2/r^2 the same thing as the coulombs law equation?
  30. J

    Confused about electric potential and electric field

    I'm confused myself about your first reply. I still struggle to understand why you can have an electric field of zero, but still have a potential. This is the statement you offered: "The absolute level of potential is meaningless. All that has a physical meaning is the difference in...
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