Physics, asked by sunilpal8807, 1 year ago

On a 120 km track a train travels the first 30 km at a uniform speed of 30 km/h . calculate the speed with which the train should move rest of the track so as to get the average speed of 60 km/h for the entire trip

Answers

Answered by danielochich
5
Average speed is equal to :

Total distance ÷ total time

Total distance = 120 Km

Let total time = t

60 = 120 / t

60t = 120

t = 2 hrs

Time taken to cover 30km is :

30 /30 = 1hr

2 - 1 = 1hr

The distance covered in the remaining one hr is :

120 - 30 = 90

Speed is thus :

90/1 = 90km/h



Answered by SaNuExTrEmE
0

                           ANSWER                            

                          In the first 30 km speed of the train, v1 = 30 km/h

                          Speed of the train in the next 90 km, v2 (to be determined)

                         Average speed = 60 km/h = (v1 + v2)/2  

                                         = (30 km/h + v2)/2  

                              → v2 = 90 km/h

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