How do I find average velocity over a given time interval?

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Answer 1 · 2015-05-17T19:36:53

Average velocity = total distance / total time

Example:
I travel from Rotterdam to Amsterdam (100 km) with an average speed of 80 km/h and return with an average speed of 120 km/h.

Then my average verlocity is NOT 100 km/h, but:

Time for the trip out: $(100km)/(80km//h)=1.25h$

Time for the trip back: $(100km)/(120km//h)~~0.83h$

Total time: $1.25+0.83=2.08h$ over $200 km$

Average velocity: $200/2.08=96.0km//h$

This may be counter-intuitive, but remember you spend more time in the slow mode than in the fast mode.