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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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lublana

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

[tex]S=ut+\frac{1}{2}at^2[/tex]

Using the formula

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

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

Length of seven cars=7L

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

[tex]7L=\frac{1}{2}\times \frac{L}{24.5}t'^2[/tex]

[tex]7\times 2\times 24.5=t'^2[/tex]

[tex]t'=\sqrt{7\times 2\times 24.5}=18.5 s[/tex]

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

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