Recent content by sea333

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    Intro Physics Books for high school physics E&M [No integrals]

    I am mainly looking for some modern book with media links in the book.
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    Intro Physics Books for high school physics E&M [No integrals]

    so you can't recommend to your students any English books?
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    Intro Physics Books for high school physics E&M [No integrals]

    If you are a high-school teacher can't you recommend a few books?
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    Intro Physics Books for high school physics E&M [No integrals]

    Is there a good "classic" book available?
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    Intro Physics Books for high school physics E&M [No integrals]

    Can you recommend introductory physics book for high school that contains E & M ? It should not have any integrals.
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    [Electrical force] 2 balls hanging from ceiling, angled

    1 - cos^2(10) + sin^2(10) = 2sin^10 because cos^2(10) + sin^2(10) = 1
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    [Electrical force] 2 balls hanging from ceiling, angled

    I have checked this and I get r = 2a*sin10
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    [Electrical force] 2 balls hanging from ceiling, angled

    I don't think I will need these advance techniques in my exercises
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    [Electrical force] 2 balls hanging from ceiling, angled

    sqrt(4a^2sin^2(10)) = 2*a*sin10 How do you get from 1 - cos^2(10) - sin^2(10) to 2 sin^2(10) ?
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    [Electrical force] 2 balls hanging from ceiling, angled

    I still don't see how this is correct as angle 10 is not adjacent to r
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    [Electrical force] 2 balls hanging from ceiling, angled

    correct solution
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    [Electrical force] 2 balls hanging from ceiling, angled

    It looks like the Tan approach was correct
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    [Electrical force] 2 balls hanging from ceiling, angled

    When I changed the sign now result looks correct. I don't think you can get r in such a way because angle 10 degrees is not adjacent to r
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    [Electrical force] 2 balls hanging from ceiling, angled

    This looks easy, but why was my attempt flawed with Tan10 ?
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    [Electrical force] 2 balls hanging from ceiling, angled

    q*q/(4*PI*Eps0*r^2) = (m*g / Cos10) * Sin10 And then just move everything except q on the right side