Given
Time taken is t=8 s.
The initial speed is u=7 m/s
The final speed is v=9 m/s.
To find
The acceleration
Explanation
We know the acceleration is the ratio of the difference in the speed to the time taken.
Thus,
[tex]\begin{gathered} a=\frac{v-u}{t} \\ \Rightarrow a=\frac{9-7}{8} \\ \Rightarrow a=\frac{2}{8}=\frac{1}{4}=0.25\text{ m/s}^2 \end{gathered}[/tex]Conclusion
The acceleration is
[tex]0.25\text{ m/s}^2[/tex]