🚀 go-pugleaf

Larry Fishbach (maven@hercules.lerc.nasa.gov) wrote:
 >In article <Pine.SGI.3.91.950329085251.21144A-100000@server.uwindsor.ca>, Maisonneuve  Michael Jaso <maisonn@server.uwindsor.ca> writes:
 >|> Ladies and Gentlemen, 
 >|> 
 >|> I have here what I can discribe only as a brutal science competition.  
 >|> This is the only event in which our school has decided to go out and look 
 >|> for serious help in.
 >|> 
 >|> Any help at all, suggestions, advice, tips...etc.  Will be appreciated.
 >|> 
 >|> The event is called "Massing a Car."
 >|> 
 >|> We will be presented with a car on a concrete floor in an auto shop and 
 >|> given a maximum of 10min to determine the mass of the car in Kg.
 >|> The car may be loaded unevenly (i.e., the weight of the car may not be 
 >|> equally distributed on the 4 tires).  The tires may or may not be of the 
 >|> same type (tread design, diameter, circumference, width etc.)
 >|> The car will remain locked during the exercise.  We may not lift the car 
 >|> in any manner, manually or mechanically.  We may not use any balances to 
 >|> measure the mass or the weight of the car directly.
 >|> We may measure any external features of the car (such as length, width, 
 >|> height, tire pressure, tire dimensions, etc.).  (We must bring our own 
 >|> measuring devices.)
 >|> Scoring is based on how close to the actual mass of the car as determined 
 >|> by the judges.  Ties will be determined by the shortest time taken to 
 >|> complete the task.
 >|> 
 >|> I can state that from previous years, time is of the essence!
 >|> 
 >|> I have given all of the information we know and would appreciate any 
 >|> responces.  
 >|> 
 >|> The date of the competition is April 29, 1995.
 >|> 
 >|> I will do my best to read the newsgroups I have posted this in as often 
 >|> as possible but unless you want to discuss an idea among others E-mail 
 >|> would be appreciated.
 >|> 
 >|> Thanks in advance for anyhelp...
 >|> 
 >|> Sean "Demetrius" Stephens
 >|> maisonn@server.uwindsor.ca
 >|> 
 >|> P.S. This is a high school competition in windsor ON, Canada.

 > Will the car be in neutral or in park or don't you know?
 >If it can be pushed you can get it to move at constant velocity
 >and measure the force you are exerting.  Estimating the coefficient
 >of rolling friction will get you the mass.

Well, I'd propose not to use friction, but acceleration.
Accelerate the car by pulling with a known and constant force 
on a horizontal surface.  Then let it go freely and determine
the speed (by measuring how far it gets in a given amount
of time).  

Patrick.


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Patrick Van Esch
http://www.iihe.ac.be/hep/pp/vanesch
mail:   vanesch@dice2.desy.de
for PGP public key: finger vanesch@dice2.desy.de