The acceleration in a time interval is given by the ratio of the total change in the velocity to the time taken.
Considering the 1st option,
The time interval is Δt=8-4=4 s
From the graph the change in the velocity during this period is
[tex]\Delta v=4-4=0\text{ m/s}[/tex]
Thus the acceleration in this interval is
[tex]\begin{gathered} a=\frac{\Delta v}{\Delta t} \\ =\frac{0}{4} \\ 0m/s^2 \end{gathered}[/tex]
Considering the second option,
The time interval is Δt=20-12=8 s
The change in the velocity in this interval is
[tex]\Delta v=[/tex]
Considering the 3rd option,
The time interval is Δt=12-10=2 s
