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i havent taken Calc yet :)Hootenanny said:Or you could use calculus.

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- #26

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i havent taken Calc yet :)Hootenanny said:Or you could use calculus.

- #27

Hootenanny

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In that case, your only option is to graph the function. If you can download a graphing program or use an online application I would do that (much easier than by hand).Alt+F4 said:i havent taken Calc yet :)

- #28

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I can use a Ti-84 i just cant seem to get the Answer they haveHootenanny said:In that case, your only option is to graph the function. If you can download a graphing program or use an online application I would do that (much easier than by hand).

I did 5Sin(2Pi60X + 25 (Phasor Angle or should a number go in there) * 120 Sin 20pi60X) = i got 561.79 instead of their answer

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- #29

Hootenanny

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Do I read it correctly? Is that what you typed into your calc?Alt+F4 said:I can use a Ti-84 i just cant seem to get the Answer they have

I did 5Sin(2Pi60X + 25 (Phasor Angle or should a number go in there) * 120 Sin 20pi60X) = i got 561.79 instead of their answer

[tex]P = V\cdot I = 120\sin(2\pi60t)\cdot\left(5\sin(2\pi60t+\Phi)\right)[/tex]

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Exactly, except for the Phasor i put in the AngleHootenanny said:Do I read it correctly? Is that what you typed into your calc?

[tex]P = V\cdot I = 120\sin(2\pi60t)\cdot\left(5\sin(2\pi60t+\Phi)\right)[/tex]

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http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa02 [Broken]

Why is Question 11 C??

Why is Question 11 C??

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- #32

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All right last question and i think i will be done

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa02 [Broken]

Question 5

Force = VB sin theta

but there is all this other stuff,

so i did

Force = A*V*B*R / (T) = .001 so why am i off by a factor of 10^-2. Thanks for everyones help

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa02 [Broken]

Question 5

Force = VB sin theta

but there is all this other stuff,

so i did

Force = A*V*B*R / (T) = .001 so why am i off by a factor of 10^-2. Thanks for everyones help

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- #33

OlderDan

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Put your calculator in radian mode and enter the phase angle in radians.Alt+F4 said:Exactly, except for the Phasor i put in the Angle

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Nope.i get 1.7E-9, 2.2E-8 unless i have to convert it somehowOlderDan said:Put your calculator in radian mode and enter the phase angle in radians.

- #35

OlderDan

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That is not the formula you need. That is for finding the field produced by a current in a wire.Alt+F4 said:http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/sp06 [Broken]

Question 11

I wanted to use this forumla B = UoI/ 2 pi R but i have no idea how to use it cause i keep getting a big number

The induced emf is the negative of the rate of change of flux through the loop. Flux is related to field strength and area. The field is constant. The area is changing at a constant rate. The current is related to the induced emf and resistance of the loop.

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- #36

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o yaaaaa thanks alotOlderDan said:That is not the formula you need. That is for finding the field produced by a current in a wire.

The induced emf is the negative of the rate of change of flux through the loop. Flux is related to field strength and area. The field is constant. The area is changing at a constant rate. The current is related to the induced emf and resistance of the loop.

- #37

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all right so why am i only counting current for one side icne 196/2 = 98Alt+F4 said:one more,

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/sp06 [Broken]

question 24.

i did this like 20 times in other exams, i dont know why it doesnt work here but

F= ILBSintheta = MG

(X)(.1)(.5) = (9.8)(1)

X = 196Amps, but the answer is 98 Amps what gives?

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- #38

OlderDan

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You are doing something wrong in your calculator. If the current and voltge were in phase you would have a maximum power of 120V*5A=600W. The phase difference reduces this somewhat, but not by a huge amount.Alt+F4 said:Nope.i get 1.7E-9, 2.2E-8 unless i have to convert it somehow

- #39

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hmm well i think there is something wrong with their calculation, i have no idea how they got 25 Degrees to .436 radians, i got .4663 radians so maybe that is why i cant get their answerOlderDan said:You are doing something wrong in your calculator. If the current and voltge were in phase you would have a maximum power of 120V*5A=600W. The phase difference reduces this somewhat, but not by a huge amount.

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Question 16 please :)

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa05 [Broken]

So i tried doing it on Calculator but since sin180 = 0 i get 0

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa05 [Broken]

So i tried doing it on Calculator but since sin180 = 0 i get 0

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- #41

OlderDan

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25/180*π = .43633 not .4663Alt+F4 said:hmm well i think there is something wrong with their calculation, i have no idea how they got 25 Degrees to .436 radians, i got .4663 radians so maybe that is why i cant get their answer

- #42

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ya i cant get the answer at all, i tried on diffrent calculators. i am postiive im typing it correctlyOlderDan said:25/180*π = .43633 not .4663

- #43

OlderDan

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Are you using the calculator to find the maximum of the product IV? How are you doing this?Alt+F4 said:ya i cant get the answer at all, i tried on diffrent calculators. i am postiive im typing it correctly

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- #45

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is there an explanation for this one or is this one of the thing you memorizeAlt+F4 said:http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa02 [Broken]

Why is Question 11 C??

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- #46

OlderDan

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When I do that I get 571.9W using their value of 0.436 for phase in radians, which is correct. What do you get?Alt+F4 said:

- #47

OlderDan

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It is not sin180. It is sin180t with t constantly changing. You need to find the maximum rate of change of the flux and use the number of turns to find the maximum emf.Alt+F4 said:Question 16 please :)

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa05 [Broken]

So i tried doing it on Calculator but since sin180 = 0 i get 0

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- #48

OlderDan

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Did you find the current in the circuit? Did you compute the voltages for each of the elements from that current?Alt+F4 said:

Why is Question 11 C??

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- #49

OlderDan

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This is from the left side. It is the only side in the magnetic field. The right side contibutes nothing.Alt+F4 said:Last Question of the day i promise :), thanks for everyones help

http://online.physics.uiuc.edu/cgi/courses/shell/phys102/fall06/prep2a.pl?practice/exam2/fa05 [Broken]

Question 3

Why is it just (3)(.7*.2*2) = .084 Why not take into account the left side. Thanks

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- #50

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same but the answer is 543 that is why im so confusedOlderDan said:When I do that I get 571.9W using their value of 0.436 for phase in radians, which is correct. What do you get?

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