Re: [Phys-l] truck mileage

["H Holmes" <rholmes@waubonsee.edu>]

Dear Physicists: 
 
This conundrum was sent to me, a lowly biologist, by a physics
professor. We had a number of conversations some years ago about my
experiences driving my son around the country for his equestrian
competitions. 
 
I can add my experiences to your conversation. My Ford F350 diesel
truck gets 15-17 mpg on the highway, depending on my speed. Add a 10,000
pound trailer and that goes down to 9-11. Load the trailer with another
5,000 pounds of horses, feed, and tack---puts me criminally overloaded,
dangerously out of control, and reduces my mileage by about 1 mpg.
 
There are two huge factors which the ag professor did not account for:
First, these trailers come with huge wind resistances, which not only
accounts for fuel economy but makes them very difficult to control in
high winds. Second, none of them have the aerodynamics of a Prius.
 
That's my two cents.
 
 
 
H. Rodney Holmes, Ph.D.
 
Department of Health and Life Sciences
Waubonsee Community College
Rt. 47 @ Waubonsee Dr.
Sugar Grove, IL 60554
 
630-466-2453 office
630-466-2441 fax (please include cover sheet)

> > > Kathy Daniel <kcdohs@comcast.net> 5/7/2008 4:02 PM >>>
I have quite an interesting problem that I cannot explain...

Our Ag teacher set up this scenario for me:

one 5000# truck gets about 18 miles per gallon
same 5000# truck pulling a 4000# trailer gets 8 miles per gallon
same 5000# truck pulling a 4000# trailer + 10000# of cows ALSO  gets 8 

miles per gallon.

Any ideas why the empty and the full trailer both get the same  
mileage?  This same pattern is also present in a different trailer and 

truck combination.

thanks,
Kathy


Kathy Daniel
Oakland High School
Murfreesboro, TN  37130
kcdohs@comcast.net 

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