Respuesta :
Answer:
a. 0.32 m/s²
b. 12.5 s
Explanation:
We know that the final velocity vf = 8 m/s, the initial velocity vi = 4 m/s and the distance traveled x = 150 m. Then, we can calculate the acceleration using the following equation
[tex]\begin{gathered} v_f^2=v_i^2+2ax \\ \\ v_f^2-v_i^2=2ax \\ \\ \frac{v_f^2-v_i^2}{2x}=a \end{gathered}[/tex]Replacing the values, we get
[tex]\begin{gathered} \frac{8^2-4^2}{150\text{ }}=a \\ \\ \frac{64-16}{150}=a \\ \\ 0.32\text{ m/s}^2=a \end{gathered}[/tex]Therefore, the acceleration of the runner was 0.32 m/s²
Now, the amount of time elapsed is equal to
[tex]\begin{gathered} a=\frac{v_f-v_i}{t} \\ \\ t=\frac{v_f-v_i}{a} \\ \\ t=\frac{8-4}{0.32} \\ \\ t=12.5\text{ s} \end{gathered}[/tex]Therefore, the amount of time elapsed during the change of velocity was 12.5 seconds.
