Sarah is running a race and is almost to the finish line. In the last 5 seconds, her velocity changes from 2m/s to 4m/s. What is her average

Question

Sarah is running a race and is almost to the finish line. In the last 5 seconds, her velocity changes from 2m/s to 4m/s. What is her average acceleration during the last 5 seconds of the race?

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Xavia 4 years 2021-09-04T09:36:18+00:00 2 Answers 8 views 0

Answers ( )

  1. bonexptip
    0
    2021-09-04T09:37:33+00:00
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    Answer:

    Solution :–

    Here

    Initial velocity = 2 m/s

    Final velocity = 4 m/s

    Time = 5 sec

    v = u + at

    4 = 2 + a(5)

    4 – 2 = a(5)

    2 = 5a

    2/5 = a

    Hence, acceleration is 2/5 m/s²

  2. haidang
    0
    2021-09-04T09:38:16+00:00
    Reply

    Answer:

    \boxed {\boxed {\sf a= \frac {2}{5} \ or \ 0.4 \ m/s^2}}

    Explanation:

    Acceleration is found by dividing the change in velocity by the time. The formula is:

    a= \frac {v_f-v_i}{t}

    where v_f is the final velocity, v_i is the initial or starting velocity, and t is the time.

    Her velocity changes from 2 meters per second to 4 meters per second in the 5 seconds. Therefore:

    v_f= 4 \ m/s \\v_i= 2 \ m/s \\t=5 \ s

    Substitute the values into the formula.

    a= \frac { 4 \ m/s- 2 \ m/s}{5 \ s}

    Solve the numerator and subtract.

    a= \frac { 2 \ m/s}{5 \ s}

    Divide.

    a= \frac{2}{5} \ m/s/s= \frac{2}{5} \ m/s^2

    This can also be written as a decimal.

    a=0.4 \ m/s^2

    Her average acceleration during the last 5 seconds of the race is 2/5 or 0.4 meters per square second.

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