Distance travelled by a train and time taken by it is shown in the following table:
Time
Distance (in km)
0
10:00 am
10:30 am
10:40 am
25
28
40
11:00 am
11:15 am
11:30 am
42
50
* Plot distance-time graph.
(ii) What is the average speed of the train?
(iii) When is the train travelling at the highest speed?
(iv) Calculate the speed of the train between 10:40 am to 11:00 am.
Answers
Answer:
Distance (km)
| * *
| *
| *
|________________________________
10:00 am 10:30 am 11:00 am
graph
(ii) Average speed of the train:
Average speed is calculated by dividing the total distance traveled by the total time taken. In this case, the total distance traveled is 50 km (from 10:00 am to 11:15 am), and the total time taken is 1 hour and 15 minutes (from 10:00 am to 11:15 am).
Average speed = Total distance / Total time
Average speed = 50 km / 1.25 hours
Average speed = 40 km/h
Therefore, the average speed of the train is 40 km/h.
(iii) When is the train traveling at the highest speed:
From the graph, we can observe that the train covers the most distance in the least amount of time between 10:40 am and 11:00 am. Therefore, the train is traveling at the highest speed during this time interval.
(iv) Speed of the train between 10:40 am to 11:00 am:
To calculate the speed between 10:40 am and 11:00 am, we need to find the change in distance and divide it by the change in time.
Change in distance = 42 km - 28 km = 14 km
Change in time = 11:00 am - 10:40 am = 20 minutes = 1/3 hour
Speed = Change in distance / Change in time
Speed = 14 km / (1/3) hour
Speed = 42 km/h
Therefore, the speed of the train between 10:40 am and 11:00 am is 42 km/h.