Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

qsx1

2. Two horizontal conducting rails are connected by a resistor R = 0.750 , as illustrated below. There is a uniform magnetic field B = 0.120 T pointing vertically downward. A conducting rod of length l = 2.20 m moves to the left along the two rails at a constant speed v = 3.90 m/s. Assume that resistance between the rod and rails is negligible. (a) What is the induced emf in the circuit? (b) What is the magnitude and direction of the current flow? (c) What is the rate of heat dissipation in the resistor? (d) What force is required to keep the rod moving at its constant speed?

  • 8 months ago
  • 8 months ago

  • This Question is Open
  1. qsx1
    Best Response
    You've already chosen the best response.
    Medals 0

    • 8 months ago
    1 Attachment
  2. qsx2
    Best Response
    You've already chosen the best response.
    Medals 0

    @theEric

    • 8 months ago
  3. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Creating multiple names is also against the Code of Conduct at http://openstudy.com/code-of-conduct I bet you want to be efficient, but this is not the way to do it. You can only learn one problem at a time. Why complicate it by trying to learn two?

    • 8 months ago
  4. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    I might be able to help with this one. Do you understand the setup?

    • 8 months ago
  5. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    there are some problems going around, i want to just finish it as soon as possible so that some problems can reduced

    • 8 months ago
  6. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    Yes, i alo attached the picture of the setup

    • 8 months ago
  7. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    So, you understand how the EMF is produced?

    • 8 months ago
  8. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    nope

    • 8 months ago
  9. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Well, when charges,\(\qquad\) like those in the rod move with respect to an electric field,\(\qquad\) like the rod is in the uniform magnetic field then the charges will experience a force, and thus there is a current. The EMF is the voltage of the electrons, I believe. I'm finding equations now.

    • 8 months ago
  10. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfor.html#c2 Lorentz Force Law, this is!

    • 8 months ago
  11. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    ohh, i got the concept

    • 8 months ago
  12. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    I'm trying to find how it's applied to the rod..

    • 8 months ago
  13. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    I would invite people to this question, but no one I fanned is on...

    • 8 months ago
  14. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    please

    • 8 months ago
  15. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    I sent a couple e-mails to people who are on and have answered many physics questions. I'll go back to seeing if I can learn how to solve this, now.

    • 8 months ago
  16. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Like, I know what direction the charges move in.. And what force each charge has.. But my mind isn't beyond that.

    • 8 months ago
  17. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    I have an idea, but I'm not sure it's valid, so I won't say it in case it's wrong.

    • 8 months ago
  18. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Oh, thank goodness! Easier than I planned: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/genwir2.html

    • 8 months ago
  19. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    So the EMF is\[EMF=v\ B\ l\ sin(\theta)\]where \(\theta\) is the angle between the velocity and magnetic field directions. Now we can move on, thank goodness. You there?

    • 8 months ago
  20. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

    • 8 months ago
  21. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Cool! So now you can calculate the EMF! That's your part a.

    • 8 months ago
  22. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    part b?

    • 8 months ago
  23. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Well, Lorentz Force Law will tell you which way the electrons will be forced! http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfor.html#c2 Look to the right hand rule.

    • 8 months ago
  24. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Let me know what you think on that.

    • 8 months ago
  25. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    think about* that.

    • 8 months ago
  26. qsx
    Best Response
    You've already chosen the best response.
    Medals 0

    i need more help :(

    • 8 months ago
  27. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Alright!|dw:1374787554478:dw| Use my drawing, and draw the magnetic field and the velocity of the rod.

    • 8 months ago
  28. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    Hmm?

    • 8 months ago
  29. theEric
    Best Response
    You've already chosen the best response.
    Medals 1

    I have to go. Take care, and good luck!

    • 8 months ago
  30. Festinger
    Best Response
    You've already chosen the best response.
    Medals 3

    I did a derivation for the formula to use here: http://openstudy.com/study#/updates/51f0facfe4b00daf471b20fe For force it is an experimental fact that \[F=qv\times B\] But the force exerted on the electrons is proportional to the speed the electrons move in the conductor, not the velocity the rod moves at. Current is \[I=nqAv_{d}\] where vd here is the drift velocity of the electrons (speed they move in current), n is number of free electrons per unit volume, A is cross sectional area of the wire and q is the charge of each electron. Now, the force on the wire is the sum of all the electrons in the conductor: \[F_{wire}=nALqv_{d}\times B\] Which reduces to\[F_{wire}=IL\times B\]

    • 8 months ago
  31. Deba_001
    Best Response
    You've already chosen the best response.
    Medals 0

    (a) e= bvl (b) direction is found by using R.H.Thumb rule (c) Heat dissipation = B2*v2* L2/R

    • 8 months ago
  32. qsx2
    Best Response
    You've already chosen the best response.
    Medals 0

    This is what i got so far a) = vBl = 3.9*0.12*2.2 = 1.03V b)Direction of the current flow is from left to right. I = /R = 1.03/0.75 = 1.37A c) Rate of heat dissipation, P = I2R = 1.41W d) Force = IBl = 0.36N

    • 8 months ago
  33. qsx2
    Best Response
    You've already chosen the best response.
    Medals 0

    @Fifciol

    • 8 months ago
  34. qsx2
    Best Response
    You've already chosen the best response.
    Medals 0

    @Festinger are my answers correct?

    • 8 months ago
  35. Festinger
    Best Response
    You've already chosen the best response.
    Medals 3

    I am not you sure what you mean by left to right, but the direction of the current is anti clockwise when viewed from the top. otherwise everything else looks fine. There are a few ways to get force for this question. 1: F=ILB 2: Power = Fv

    • 8 months ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.