NCERT Solutions Curiosity Chapter 8 .3 Speed — Activity 8.4: Let us calculate

Book page 114 & 1158 Updated on2026-09-05

Q1.
Calculate the speed of the train between the two stations and record it in Table 8.2.
Answer

Use the railway timetable: note the distance to the next stopping station and the difference between the departure time from your station and the arrival time at the next one, then divide.

Speed of the train = Distance till the next station ÷ Time taken till the next station

Sample answer (nearest railway station: Bhopal Junction) — fill your own timetable values in the same way:

Table 8.2: Finding the speed of trains
S.No.Name of the trainName of the next stationDistance till the next station (km)Time taken till the next station (h)Speed of the train between these two stations (km/h)
1.Vande Bharat ExpressJhansi2913.00291 ÷ 3.00 = 97 km/h
2.Shatabdi ExpressJhansi2913.50291 ÷ 3.50 = 83.1 km/h
3.Punjab Mail (Express)Bina1392.25139 ÷ 2.25 = 61.8 km/h
4.Intercity ExpressVidisha540.7554 ÷ 0.75 = 72 km/h
5.Passenger trainVidisha541.5054 ÷ 1.50 = 36 km/h
Watch the time carefully: a timetable gives clock times, not durations. If a train leaves at 06:20 and reaches at 07:50, the time taken is 1 h 30 min = 1.5 h, not 1.30 h. Always turn the minutes into a fraction of an hour (30 min = 0.5 h, 45 min = 0.75 h, 15 min = 0.25 h).
Q2.
Compare the speeds of the trains. Which is the fastest train?
Answer

The train which has covered the maximum distance in unit time is the fastest train — that is, the one with the highest speed. In the sample table above, that is the Vande Bharat Express at 97 km/h.

Arranged from fastest to slowest: Vande Bharat (97 km/h) > Shatabdi (83.1 km/h) > Intercity (72 km/h) > Punjab Mail (61.8 km/h) > Passenger train (36 km/h).

Why the longest journey is not automatically the fastest: Punjab Mail travelled 139 km while the Intercity travelled only 54 km, yet the Intercity is the faster of the two. A big distance in a big time can still mean a small speed. Only distance per hour settles the matter.
Did you know? Superfast trains stop at fewer stations, and every stop costs slowing down, waiting and speeding up. That is a large part of why a passenger train on the same track is so much slower.
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