There CAN be action in the direction of the torque vector if it is not
opposed by a balancing torque. Newton's second law can be written in
rectilinear form as
a = F / m
and in rotational form as
a = T / I
where, in the latter equation, a (proxy for alpha) is angular
acceleration, T (proxy for tau) is the NET torque, and I is the moment
of inertia. Of course, one must realize that the vector direction for
angular acceleration (and for angular velocity and angular displacement)
is along the axis of rotation. To find this direction for angular
displacement, consider the direction a normal ("right-hand threaded")
screw would advance if turned in the manner of that angular
displacement.
Of course, if the torque is counterbalanced then there will be no
angular acceleration (though there may well be a non-zero angular
velocity). This again is exactly analogous to the rectilinear version of
Newton's second law of motion.
Jim
Nat Hager III wrote:
>
> It took me a while to get used to, since there is no "action" in the
> direction of the vector, only a mathematical formalism.
>
> But it is a convenient way of uniquely defining the 1) speed, 2)
> orientation, and 3) clockwise/counterclockwise sense of a spinning object -
> such as a gyroscope, planet, or electron.
>
> Nat
>
> > Nat Hager wrote:
> > > It's a convenient formalism used in rotational mechanics.
> >
> > For those of us who are not practitioners of rotational mechanics, it's a
> > somewhat inconvenient formalism, as it violates the usual mathematical
> > definition of vector.
> >
> > However, thanks for adding to my relatively limited knowledge of
> > that field.
> > <g>
--
Metric Methods(SM) "Don't be late to metricate!"
James R. Frysinger, CAMS http://www.metricmethods.com/
10 Captiva Row e-mail: [EMAIL PROTECTED]
Charleston, SC 29407 phone/FAX: 843.225.6789
