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From: carl@aoa.UUCP (Carl Witthoft)
Newsgroups: net.physics
Subject: Re: Question... [On tilt-meters in off-road vehicles]
Message-ID: <271@aoa.UUCP>
Date: Tue, 27-Aug-85 07:52:34 EDT
Article-I.D.: aoa.271
Posted: Tue Aug 27 07:52:34 1985
Date-Received: Thu, 29-Aug-85 20:52:43 EDT
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Reply-To: carl@aoa.UUCP (Carl Witthoft)
Distribution: net
Organization: Adaptive Optics Assoc., Cambridge, Mass. USA
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>Another thought about gyroscopic properties of this system -- the
>gyroscopic behavior of the vehicle as a whole is probably insignificant
>considering how slowly it is revolving, but the gyroscopic behavior of
>the *wheels* is probably significant. My first guess would be that the
>gyroscopic behavior of wheels would tend to stabilize the vehicle
>against rolling, but I can't seem to visualize the vectors -- intro
>physics was too long ago.
>
This and many other responses to the original question (tipping of the truck)
seem to be trying too hard. The truck simply tips when there is a net force
on any vector not parallel to the perpendicular to  the truck's frame. WHether
this is due to sitting on a hill, turning sharply, or turning while speeding up
(these last two, by the way, both are best viewed in terms of angular momentum
and torque--any change in the velocity VECTOR means there is acceleration),is
irrelevant to the final effect. BTW, the torque generated by the wheels
does make some difference. Go look at (e.g. Halliday&Resnick) pictures of
a top precessing, and you'll see that a car will behave more stably turning
to the left than to the right ( unless I got those switched again??).

But why worry about tipping-- just use a trapeze harness (<==))).



        Darwin's Dad (Carl Witthoft)
	...!{decvax,linus,ima,ihnp4}!bbncca!aoa!carl
	@ Adaptive Optics Assoc., 54 Cambridgepark Dr.
	Cambridge, MA 02140	617-864-0201

	"Put me in, Coach. I'm ready to play today.
	 Look at me! I can be centerfield."