Question

Fig 8.11 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?

Answer 1

Answers:

(a)

Object B

(b)

No

(c)

5.714 km

(d)

5.143 km

(a)

∴Speed = slope of the graph

Since the slope of object B is greater than objects A and C, it is travelling the fastest.

(b) All three objects A, B and C never meet at a single point. Thus, they were never at the same point on road.

(c)

On the distance axis:

7 small boxes = 4 km

∴1 small box

Initially, object C is 4 blocks away from the origin.

∴Initial distance of object C from origin=

Distance of object C from the origin when B passes A = 8 km

Distance covered by C

Hence, C has travelled a distance of 5.714 km when B passes A.

(d)

Distance covered by B at the time it passes C = 9 boxes

Hence, B has travelled a distance of 5.143 km when B passes A.