🚀 go-pugleaf

John Mallinckrodt <ajmallinckro@CSUPOMONA.EDU> wrote:

>Mervin Koehlinger writes:

>>Now we're getting to the heart of the matter.  It's not individual forces
>>that produce rotation, but couples!
>>
>>Forces produce translation; couples produce rotation.

I prefer: Forces cause acceleration (not necessarily movement)
while couples cause a torque (not a rotation).

>Sorry, that does not compute.  A rod in "free space" will be set into
>rotation by a SINGLE force as long as that force is not applied along
>a line that passes through the rod's center of mass.

John: It DOES compute. Imagine the impact resulted in pure
movement without rotation. More exactly spoken: the result would
be a linear acceleration of the CM. By Newton's laws (inertia...)
we know that from this acceleration the CM should "feel" (I just
can't remember the correct term) a corresponding force pointing
in the opposite direction. So these two forces build a couple and
produce a torque.

bye, bye
	Guntbert
------------------------------------------------
Guntbert Reiter : guntbert@borg-6.borg-graz.ac.at
HTL Weiz
Graz
Austria