Search results

  1. R

    KCL and First order circuit theory

    Can you please explain what are the correct equations for node A and B?
  2. R

    KCL and First order circuit theory

    r I understand your point. Because the form tells me I have a decaying voltage, I need to have a negative argument to e. I need to apologize for not making my question very clear. I know the first form is correct (Node A) but is the second form equally valid but incorrect? And because they are...
  3. R

    KCL and First order circuit theory

    My question applies to the case when the switch opens. By applying KCL in order to get a first order diff equation, the following problem arises when I choose different current directions (which shouldn't happen because KCL says the current direction doesn't matter because it will be fixed...
  4. R

    Griffith's 3.33

    I am "continuing this thread" in hopes of asking questions that deal with the meaning of the question. https://www.physicsforums.com/threads/griffiths-e-m-3-33-write-e-field-of-dipole-moment-in-coordinate-free-form.359973/ 1. Homework Statement Show that the electric field of a "pure" dipole...
  5. R

    Why do the face diagonals have different angles?

    Oh so that's what face diagonals mean. :blushing: Thank you.
  6. R

    Why do the face diagonals have different angles?

    Isn't the line from (0,0,1) to (1,1,1) a face diagonal? The angle made with the edge and the inside diagonal is the angle of the face diagonal, assuming the face diagonal is (0,0,1) to (1,1,1), right?
  7. R

    Why do the face diagonals have different angles?

    Homework Statement Find the angle of the face diagonals of a (unit) cube. I agree with this solution, but I have a problem with another face diagonal: the face diagonal from the angle (0,0,1),(0,0,0), and (1,1,1). Homework Equations dot product cos-1(a.b/ (|a||b|) The Attempt at a Solution...
  8. R

    Norton's Theorem

    Thanks again!
  9. R

    Norton's Theorem

    Follow up question on using QUCS: I'm trying to make a current controlled voltage source matching this diagram...: Im not sure how exactly the current controlled voltage source is used in qucs.. Examples help, but I didnt know the right name for it in the examples given in qucs <Qucs...
  10. R

    Norton's Theorem

    I was able to find the Voltage between the open circuit using Thevenin and Node analysis: I got Vth = ~10.8 V (making Vy facing positive and Vx near negative), and Rth = 33/5. So the short circuit current is 10.8/6.6=1.6464 and current division between the load and 6.6 KOhms makes the load...
  11. R

    Norton's Theorem

    At first I didn't know what you meant by "driving the current through the 6 k "load" using whatever means you wish." but with FOIWATER's picture: I am able to understand now. Thank you! I will try my best to solve this using the techniques you suggested!
  12. R

    Norton's Theorem

    Homework Statement Find Io using Norton's Theorem Homework Equations The Attempt at a Solution I broke it into the following circuit: I would like to break it down some more but if I open the node between 3k and 6k (ohms), and 6k and 6k (ohms), I run into problems.... What should I do...
  13. R

    Given a piston find pressure

    Homework Statement Find the gauge pressure of a piston-cylinder system, assuming that the piston perfectly covers the cylinder. The piston's radius is 5 cm, its mass is 3kg, and the force being applied to it is 75N in the same direction as gravity. Looks like this picture...
  14. R

    Engineering Engineering or something more?

    This gave me a new perspective. Thank you.
  15. R

    Engineering Engineering or something more?

    How would this statement apply to math and physics majors? Is it the discovery part that allows these scientists (or mathematicians) to fit society's needs? Aren't these majors learning in and of themselves? I said in my original post that I wanted to apply the knowledge.
  16. R

    Engineering Engineering or something more?

    I am a freshman mechanical engineering. I have been exposed, to some extent, mechanical/materials, robotics(electrical), and I'm headstrong about not doing civil. I considered computer science, but I'm glad I didn't because it seems that not much calculus (math) is required for the major. I...
  17. R

    Acceleration does not matter when driving

    My professor's proof. Let me fix the equation that my professor gave. The ##W_{engine}=## is the correct formula my prof gave. W_{res} = \frac{ \rho D A v^2}{2}\\ \Delta KE = W_{engine} - W_{Res}\\ From this we get W_{engine} = 1/2 m {v_f}^2 + \frac{\rho D A v^4}{8a} I didnt want to...
  18. R

    Acceleration does not matter when driving

    In my physics lecture, my professor "proved" that acceleration does not affect the amount of energy used in driving a car. Assume car is driven along flat road. In the short, (assume air resistance is neglected, and the W done by the car's engine, W_{engine} is non conservative, \Delta PE...
  19. R

    Textbook made mistake in algebra, help

    It came with the webassign package. So it's hard to tell it's from the book or supplements because even the chapters look like supplements (i.e. each chapter and section is a weblink to a different one-page webpage)
  20. R

    Textbook made mistake in algebra, help

    Stupid wrong books. Paid good money... Alright I really like SteamKing's answer. Clearly states how the t went missing. Thanks. Really helps
  21. R

    Textbook made mistake in algebra, help

    The page is attached as an image.
  22. R

    Textbook made mistake in algebra, help

    I hope this isn't illegal but I would like to copy the webpage the page of the textbook to show you guys the problem. Will this be illegal?
  23. R

    Textbook made mistake in algebra, help

    Homework Statement There is an image but I will reiterate my problem. The writer is solving for t. Okay, easy enough. Homework Equations y-y0 = v0 t + 1/2 a t^2 Textbook says t = sqrt( (2(y-y0) - 2 v0) / a ) The Attempt at a Solution Shouldn't it be t = sqrt( (2(y-y0)...
  24. R

    Dimensional Analysis: Inverse Cosine

    If a equals an unknown dimension (whose units may equal to M^-2) then I completely understand. If a means acceleration, then I think there is a problem. Cos() will not equal a ratio if a equals acceleration. I can kinda sleep better tonight lol.
  25. R

    Dimensional Analysis: Inverse Cosine

    I just want to add, I want to ask my prof. but I'm nervous, I'm a freshman, and I dont know when would be appropriate, since class time = lecture time, not homework help time... Is that what office hours are for?
  26. R

    Dimensional Analysis: Inverse Cosine

    Sorry I forgot to press upload, its there now
  27. R

    Dimensional Analysis: Inverse Cosine

    Theres the equation see attached
  28. R

    Dimensional Analysis: Inverse Cosine

    I think we are stuck again... this was my original problem. I will take a picture and host it on this site.
Top