Physics Problem Velocity Mathematical?
In dirivng the usual route to school, a student computes the average speed for the trip to be 20.km/h. On the return trip along the same route, there is less traffic and the average speed is 30.km/h. What is the average speed for the entire trip?
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This is one of those counter-intuitive problems ...
... the average speed WON'T BE 25 km/h!
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Average speed = (total distance)/(total time)
Let's say that the distance to school = D km.
The total distance to and from school = 2D km.
Total time = D/20 + D/30
= 3D/60 + 2D/60
= 5D/60
= D/12
Average speed = 2D ÷ D/12
= 2D * 12/D
= 24
The average speed for the entire trip is 24 km/h.
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