Re: Truck stopping distances?

[Joseph Bellina <jbellina@SAINTMARYS.EDU>]

Second  shot...there will be many more.

Its the same pavement, but not the same tires...but I don't think that
is a big issue.  I suspect that the limiting factor is the temperature
of the brake pads, since if they get too hot, the friction coefficient
drops catastrophically.
So heavier trucks have more KE...takes more work to stop
them...generates more temperature increase, unless you limit the
rate of loss of mechanical energy by not braking so hard...hence the
longer stopping distance.

have a nice day

ps...lets not start another debate of the language of energy exchanges.

 On
Fri, 1 Mar 2002, Scott Goelzer wrote:

> Why does it take a truck further to stop than a car? Data on many web sites
> gives about a 50% increase in stopping distances.
>
> BUT
>
> HS physics friction problems typically ask students to calculate the
> stopping distance of a vehicle with speed x and COF y. This shows that the
> mass of the object is cancelled when finding the acceleration and therefore
> should be independent of the stopping distance.
>
> Same tires, same pavement.
> What is different about the braking systems?
>
> Web searches only reveal that the distances are greater. No mention of why -
> besides the fact that trucks are heavier - useless.
>
> Scott
>
>
>
> *****************************
> S.Goelzer
> Physics Teacher
> Coe - Brown Northwood Academy
> Northwood NH 03261
> 603-942-5531 ext43
> sgoelzer@coebrownacademy.com
> *****************************

Joseph J. Bellina, Jr.               219-284-4662
Associate Professor of Physics
Saint Mary's College
Notre Dame, IN 46556