Understanding Average Speed Calculations

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Homework Help Overview

The discussion revolves around calculating the average speed of a motorist who travels different distances at varying speeds. The specific scenario involves traveling 30 miles at 60 mph and 60 miles at 30 mph.

Discussion Character

  • Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to compute average speed using the formula distance over time but questions the result they obtained. Other participants explore the reasoning behind the average speed calculation and discuss why a simple average of speeds is not applicable in this context.

Discussion Status

The discussion includes attempts to clarify the average speed calculation, with some participants suggesting alternative reasoning. There is an acknowledgment of the complexity of the problem, and while one participant expresses confidence in their understanding, the overall conversation remains exploratory.

Contextual Notes

Participants are considering the implications of traveling different distances at different speeds, and there is a mention of the assumption that constant speeds are maintained during each segment of the journey.

rcmango
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Homework Statement



there's a motorist that travels 30 miles at 60 mph, and another 60 miles at 30 mph.


Homework Equations





The Attempt at a Solution



The average speed of the motorist is 36 mph
how was this computed?

i know avg speed is distance / chng of time

however 30+ 60 divided by 60 + 30 is not 36.
need help.
 
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Please write the full question.
 
...nevermind i think it got it,

since he's traveling only half the distance of what speed he's going, then he probably only went about 30 minutes, and then the oppositive of that with the other, which is 2 hrs, then distance of 90 / 2.5 hrs is the avg speed of 36 m/s

thanks anyway.
 
good!
just to, may be, boost up your knowledge:
can you tell, why vaverage = (v1 + v[2)/2 is not applicable here? {Note, it would give 45mph}
Also, note that constant speed is provided in either part of the motion.
 

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