Related to average speed.

Asked by  | 28th Jul, 2008, 05:23: PM

Expert Answer:

average speed =v1 = 20km/hr

average speed v2 = 40km/hr

Let the distance be x. Then time taken to make the trip is x/20.

For return trip distance is again x. Time taken to make the return trip is x/40.

Total distance = x+x =2x

Total time taken = x/20 + x/40

Average speed = 2x / (x/20 + x/40) = 2x / (3x/40) = 80/3 = 26.67 km/h.

If it was given in the question that the body has a constant acceleration all throughout the journey then for average speed we can use (u+v)/2 = 30km/h

 

Answered by  | 30th Jul, 2008, 07:10: AM

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