ANSWER

ANSWER
The area of the shaded rectangle is;

b) To estimate the change in the train's position on the time interval [2,6]. The constant velocity as measured at the midpoint of the interval equals;

Hence, the midpoint of the interval is 4 sec.
From the graph, at t= 4 sec, the velocity is 80ft/sec.
During the interval [2,6] which is 4sec.
The change in position of the train is;
