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Homework Help: Alternating current, voltage, sinusoids

  1. Mar 9, 2014 #1
    1. The problem statement, all variables and given/known data

    Consider v1 = 30 sin(ωt + 10º) and v2 = 20 cos(ωt - 40º)

    A: v1 is in advance to v2
    B: v1 differs 50º from v2
    C: v2 is in advance to v1
    D: v1 is in quadrature to v2

    2. Relevant equations
    3. The attempt at a solution

    I think the correct answer is A because v1's angle is nearer -∏/2 than v2's.
    Does this make any sense?

    Thanks for any help.
    Last edited: Mar 9, 2014
  2. jcsd
  3. Mar 9, 2014 #2


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    hi znaya! :smile:

    hint: 20 cos(ωt - 40º) = 20 sin( … ) ? :wink:
  4. Mar 10, 2014 #3
    20 cos(ωt - 40º) = 20 sin(ωt + 50º), right?

    v1 is in advance, right?
  5. Mar 10, 2014 #4


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    right! :tongue2:
    i can never remember which way round "in advance" is :redface:

    i'll take your word for it! :smile:
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