Question 6
Fig below shows the distance-time graph of three objects A, B and C. Study the graph and answer the following questions:
(a) Which of the three is travelling the fastest?
(b) Are all three ever at the same point on the road?
(c) How far has C travelled when B passes A?
(d) How far has B travelled by the time it passes C?
(a) As the slope of line B is the greatest, hence, B is travelling at the fastest speed.
(b) No, as the three lines do not intersect at a single point.
(c) As there are 7 unit areas of the graph between 0 and 4 on the Y axis, 1 graph unit equals km.
As the initial point of object C is 4 graph units away from the origin, its initial distance from the origin is 4 x km = km
When B passes A, the distance between the origin and C is 8 km.
∴ total distance travelled by C in this time = 8 – km = 5.71 km
(d) Total distance travelled by B when it crosses C = 9 x = 5.14 km