On a 150 m straight sprint, a cyclist accelerates from rest for 4.5 s at 3.8 m/s2. How long will it take her to complete the 150 m track, as

Question

On a 150 m straight sprint, a cyclist accelerates from rest for 4.5 s at 3.8 m/s2. How long will it take her to complete the 150 m track, assuming she maintains her speed for the remaining part of the track?

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Ngọc Khuê 4 years 2021-09-04T06:12:04+00:00 1 Answers 1 views 0

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  1. Dulcie
    0
    2021-09-04T06:13:34+00:00
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    Answer:

    It takes 6.52 s to complete the 150 m track.

    Explanation:

    Let’s find the position of the cyclist during the acceleration.

    x_{1}=v_{0}t+0.5at^{2}

    x_{1}=0.5(3.8)(4.5)^{2}

    x_{1}=38.48\: m

    Now, the final speed at this distance will be:

    v_{f}=v_{0}+at

    v_{f}=3.8*4.5

    v_{f}=17.1\: m/s

    Now, we know that x(tot) = 150 m, the remaining part will be:

    x_{2}=150-38.48=111.5\: m

    Therefore, the time is:

    t=\frac{x_{2}}{V_{f}}

    t=\frac{111.5}{17.1}

    t=6.52\: s

    I hope it helps you!

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