Question

A tarin travels with a speed of 60 $m{h}^{-1}$ from station A and station B and then comes back with a speed 80 $m{h}^{-1}$ from station B to station A.Find:(i) the average speed, and (ii) the velocity of train.

Answer 1

Let ‘s’ be the distance between stations A and B.
(i) Average speed = Total distance/total time taken
Here, total distance = s + s = 2s
Total time taken = Time taken to travel from A to B + Time taken to travel from B to A.
= [(s/ 60) + (s/ 80)] s
= [ 140 s / 4800] s

(ii) Average velocity = Displacement/total time taken
Because the train starts and ends at the same station, the displacement is zero. Thus the average velocity is zero.