A bus makes a trip according to the position–time graph shown in the illustration. What is the average acceleration (in km/h2) of the bus for the entire 3.5-h period shown in the graph?

Answer 1

I'd say that the velocity at the beginning of the trip was around
V1 = 40km / 1h → by reading the graph
and at the end of the trip was
V2 = (45 - 57)km / (3.5 - 2.2)h = -9.2 km/h → also estimating from the graph

a = (V2 - V1) / t = (-9.2 - 40)km/h / 3.5h = -14 km/h²
Not sure, though.

Answer 2

Mr. Charles Jackson leaves at 9 am with a group of students. They travel 350 km before they stop for lunch. Then they travel an additional 250 km until the end of their trip at 3 pm. What was the average speed of the bus?