1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

It's me again. need somebody to check my answer

  1. Apr 7, 2004 #1
    Hi all,

    it's me again... sorry but this is the only place where I learn most of my physics from... pls kindly check my answer and for the last part... I found the angle but don't know how to convert it to (rad)... pls guide me...thanks

    A series RCL circuit with L= 6.5 mH, C=3.7uF, and R = 5.5ohm is driven by a generator with a maximum emf of 197 V and a variable angular frequency w.

    (a) Find the resonant frequency . (Unit: rad/s)

    6.45E3 rad/s

    (b) Find I(rms) at resonance when w=7.0E3 rad/s . (Unit: A)

    25.3 A

    (c) Find X(c) when w=7.0E3 rad/s. (Unit: ohm)

    38.6 ohm

    (d) Find X(L) when w=7.0E3 rad/s. (Unit: ohm)

    45.5 ohm

    (e) Find Z when w=7.0E3 rad/s. (Unit: ohm)

    8.82 phm

    (f) Find I(rms) when w=7.0E3 rad/s. (Unit: A)

    15.8 A

    (g) Find the phase angle when w=7.0E3 rad/s. (Unit: rad)

    phase angle = inverse tan ((45.5-38.6) / 5.5) = 51.4

    answer: I found the angle to be 51.4 degrees but how do I convert it to unit - rad?

    thanks
    cseet
     
  2. jcsd
  3. Apr 7, 2004 #2
    If I'm not mistaken this is a conversion between degrees and radians.

    [tex]\frac{2 \pi}{360} = \frac{x}{51.4}[/tex]

    and solve for x. Don't factor out [tex]\pi[/tex], use it in your answer. For example [tex]x = 0.98 \pi[/tex]
     
    Last edited: Apr 7, 2004
  4. Apr 7, 2004 #3
    All answers are correct (good job!) except for (b) which I cannot confirm nor deny. I still don't understand the meaning of "I(rms) at resonance when w=7.0E3 rad/s" when the only resonance frequency is 6.45E3 rad/s. If they only want you to find I(rms) at w=7.0E3 rad/s, then the answer should be the same as (f), 15.8A.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: It's me again. need somebody to check my answer
Loading...