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Math Help - [SOLVED] Vectors: Work Question(Dot Product)

  1. #1
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    [SOLVED] Vectors: Work Question(Dot Product)

    If a 10N force, acting in the direction of the vector (1, 1), moves an object from P(-2, 1) to Q(5, 6), calculate the work done. The distance is in metres.

    The work formula is W = F dot D = |F||d|Cos(theta)

    Please and thanks
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  2. #2
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    Quote Originally Posted by narutoblaze View Post
    If a 10N force, acting in the direction of the vector (1, 1), moves an object from P(-2, 1) to Q(5, 6), calculate the work done. The distance is in metres.

    The work formula is W = F dot D = |F||d|Cos(theta)

    Please and thanks
    I hope this reply doesn't come too late ...

    1. Calculate the vector \vec F with |\vec F| = 10:

    \vec F = 10\cdot (1,1)\cdot \dfrac1{|(1,1)|} = (5\sqrt{2}\ ,\ 5\sqrt{2})

    2. Calculate the vector

    \overrightarrow{PQ} = \vec d =(5-(-2), 6-1) = (7, 5)

    3. As you've stated the work is

    W=\vec F \cdot \vec d That means:

    W = (5\sqrt{2}\ ,\ 5\sqrt{2}) \cdot (7, 5)=60\sqrt{2} \approx 84.85\ Nm
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    Just in time thanks!
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