Question

on a 120km long railway track , a train travels the first 80km at a uniform speed of 160km/h. calculate the speed with which the train should move to the rest of the track if the average speed is 80km/h for the entire trip.

done

Answer 1

Using formula ....
V= 2v1v2/v1+v2
Substituting values:
80= 2×160×v2/160+v2
12800 + 80v2 = 320v2
240v2 = 12800
v2 = 53.333 km/h
or 14.814 m/s