You are at a train station, standing next to the train at the front of the first car. The train starts moving with constant acceleration, an

Question

You are at a train station, standing next to the train at the front of the first car. The train starts moving with constant acceleration, and 7.0 s later the back of the first car passes you. Part A How long does it take after the train starts moving until the back of the seventh car passes you

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Nguyệt Ánh 3 years 2021-08-14T17:53:22+00:00 1 Answers 80 views 0

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    2021-08-14T17:55:20+00:00

    Answer:

    18.5 s

    Explanation:

    We are given that

    Time,t=7 s

    Number of  cars=7

    Initial velocity =u=0

    Length of  a car=L

    S=ut+\frac{1}{2}at^2

    Using the formula

    L=0+\frac{1}{2}(7)^2a=24.5a

    a=\frac{L}{24.5} m/s^2

    Length of seven cars=7L

    7L=0+\frac{1}{2}(\frac{L}{24.5}t'^2

    7L=\frac{1}{2}\times \frac{L}{24.5}t'^2

    7\times 2\times 24.5=t'^2

    t'=\sqrt{7\times 2\times 24.5}=18.5 s

    Hence,it takes 18.5 s after the train starts moving until the back of the seventh car passes you

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