ANSWER
C. 5 seconds to 7 seconds
EXPLANATION
This is a velocity time graph.
We can read the final velocity, v,the initial velocity u and the time easily from the graph.
See attachment for the initial and final velocities on each time interval.
So we can use either of the following equations to calculate the distance traveled.
[tex]s=ut+\frac{1}{2}at^2[/tex]
Or
[tex]s=(\frac{u+v}{2})t[/tex].
During the time interval 0 to 3, the distance traveled is,
[tex]s=(\frac{10+6}{2})3=24m[/tex].
During the time interval 3 to 5 seconds, the distance traveled is,
[tex]s=(\frac{6+5}{2})2=11m[/tex].
During time interval, 5 to 7 seconds the distance traveled is,
[tex]s=(\frac{5+4.9}{2})2=9.9[/tex].
[tex]\Rightarrow s\approx 10m[/tex]
During time interval 7 to 8 seconds the distance traveled is
[tex]s=(\frac{4.9+3}{2})1=3.95m[/tex].
During time interval 8 to 10 seconds the distance traveled is
[tex]s=(\frac{3+0}{2})2=3m[/tex].
The correct answer is C.
