A car is on cruise control at v=30m/s. If the wind resistance is equal to. F=0.42v² what energy will the car expend to drive 1km? A)45

Question

A car is on cruise control at v=30m/s. If the wind resistance is equal to. F=0.42v² what energy will the car expend to drive 1km?
A)450J
B)378J
C)12.6J
D)378kJ

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RI SƠ 1 year 2021-07-27T16:07:18+00:00 1 Answers 13 views 0

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  1. linhdan
    0
    2021-07-27T16:08:33+00:00
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    Answer:

    D)378kJ

    Explanation:

    Applying,

    E = F×d……………. Equation 1

    Where E = Energy expanded by the car, F = Wind resistance, d = distance

    From the question,

    F = 0.42v²………… Equation 2

    Susbtitute equation 2 into equation 1

    E = 0.42v²d………….. Equation 3

    Given: v = 30 m/s, d = 1 km = 1000 m

    Substitute these values into equation 3

    E = 0.42(30²)(1000)

    E = 378000

    E = 378 kJ

    Hence the right option is D)378kJ

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