Smile 發問於 科學及數學數學 · 1 月前

Maths problem: why answer is d, thanks?

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    1 月前
    最愛解答

    Question:

    The base diameter of a cylindrical pipe is 3.5 cm. If water flows into the pipe at a speed of 0.9 m/s, find the volume of water flowing into the pipe in one minute.

    (Give your answer correct to the nearest cm³.)

    A. 9 cm³  B. 520 cm³  C. 866 cm³  D. 51954 cm³

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    Solution:

    The base area of the cylindrical pipe = (3.5/2)²π = 49π/16 cm²

    ∵ Water flows into the pipe at a ''speed'' = 0.9 m/s

    The volume of water flowing into the pipe in 1 second

    = (49π/16 cm²) (0.9 m/s) (1s)

    = (49π/16 cm²) (0.9 m)

    = (49π/16 cm²) (90 cm)

    = 2205π/8 cm³

    The volume of water flowing into the pipe in one minute

    = The volume of water flowing into the pipe in 1 second × 60

    = (2205π/8 cm³) (60)

    = 51954 cm³ ...... ( corr to the nearest cm³ )

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    Water is flowing into the pipe.

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