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jacob s a posé la question dans Science & MathematicsMathematics · il y a 1 décennie

Find the work done by F=(2xy^3)i+(4x^2y^2)j in moving a particle once counterclockwise around the curve C: the?

Find the work done by F=(2xy^3)i + (4x^2y^2)j in moving a particle once counterclockwise around the curve C: the boundary of the "triangular" region in the first quadrant enclosed by the x-axis, the line x=1, and the curve y=x^3.

3 réponses

Pertinence
  • il y a 1 décennie
    Réponse favorite

    ∇ x F = ∂/∂x [4x²y²] - ∂/∂y [2xy³]

    = 2xy² k

    ∮c F·dr = ∫∫ ∇ x F · n dS ............. Stokes' or Green's in the x-y plane

    ... n dS = <0,0,1> dx dy for positively oriented curves the x-y plane

    = ∫∫ <0,0,(2xy²)>·<0,0,1> dx dy

    = ∫∫ 2xy² dx dy

    {(x,y) | 0 ≤ x ≤ 1 , 0 ≤ y ≤ x³}

    = 2/3 ∫ x^10 dx

    {(x) | 0 ≤ x ≤ 1}

    = 2/33

    Answer: 2/33

  • Mr N
    Lv 5
    il y a 1 décennie

    Work is defined as the definite integral of F(Force) w.r.t. s(displacement), and remember that F and s are vectors. Work done is a scalar quantity, so just calculate separately for displacement along the x-axis, the line x = 1 and the curve y = x^3. e.g., for y = x^3, s = (x)i + (y)j = (x)i + (x^3)j. So, ds = { i + 3(x^2)j }dx. And F = (2(x^4))i + 4(x^4)j. Now find the definite integral of F w.r.t. s with x ranging from 1to 0( draw graph to understand ). Similarly calculate Work(s) in rest of the 2 cases( don't ignore signs ) and just add all of them up. You will get a negative answer

  • il y a 4 ans

    counterclockwise. yet as quickly as I write my calling enjoying cards @ paintings, I purely began to jot down them clockwise by way of fact it leaves me a tiny little bit of greater area to end w/the date. VERY exciting question.

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