On a 120 km long railway track, a train travells the first 80 km at a uniform speed of 160km/h. calculate the speed with which the train should move rest of the track so as to get the average speed of 80 km/h for the entire trip
Answers
Answered by
1
Answer:
40km/hr
Explanation:
as the total distance is 120km and we want the speed to be 80km/hr
so it should take 1.5 hour in the journey
s=120km
v=80km/h
t = s/v = 120/80= 1.5
in the 1st half
s = 80km
v = 160km/hr
it took t = s/v = 0.5 hour.
now for the 2nd half
s = 120 - 80 = 40 km
t = 1.5 - 0.5 = 1 hour
v = ?
v = s/t = 40km/hr.
thanks
Answered by
0
Answer:
Average speed=Total distance Total time taken
V
av
=
t
d
ort=
V
av
d
For 120 km,
t=
60 km/hr
120 km
=2 hr ......(i)
For 1st 30 km,
t
1
=
30 km/hr
30 km
=1 hr
For remaining 90 km,
t
2
=t−t
1
=2−1=1 hr
speed=
time
distance
or v
2
=
t
2
d
2
=
1
90
=90 km/hr
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