raju travels half of the distance between 2 city with a speed of 30m/s and remaining half with a speed of 40m/s. find the average speed and average velocity of Raju
Answers
Answer:
By “half its journey,” do you mean by time or by distance?
By time, I mean the train traveled for, say, one hour at 30 m/s and one hour at 40 m/s.
By distance, I mean the train traveled, say, 100 km at 30 m/s and 100 km at 40 m/s.
Either could be seen as “half [the] journey,” but they have somewhat different results.
If we’re talking equal by time, then the train traveled 108 km at 30 m/s and then 144 km at 40 m/s. The total distance would be 252 km or 252000 m and the total time would be 7200 s. The average speed would then be 35 m/s, which is probably not a surprise to most casual observers.
For equal by distance, lets figure 100 km at 30 m/s would take 3333.3333 s and 100 km at 40 m/s would take 2500 s. The total distance divided by total time would be 200 km or 200000 m / 5833.3333 s, or 34.2857 m/s. This is what Paul Fournier and Thomas Greco also correctly answered with.
I think what most people get confused on in this type of problem is that they probably understand it to be based on distance (equal in this case), but then inadvertently calculate based on time.
