Re: Pendulum acceleration

[Ludwik Kowalski <kowalskiL@MAIL.MONTCLAIR.EDU>]

In other words, the NET FORCE, and thus the acceleration,
is zero at the bottom and non-zero at an angle, large or small.

Mark Sylvester wrote:

> on At 22:04 23/10/01 -0500, Herb Schulz wrote:
> > > Since gravity is what causes a pendulum to move,
> > > neglecting air friction and differences in direction etc.,
> > > will the bob experience the same magnitude of
> > > acceleration though out it swing.  I want to know if the
> > > change in speed is the same. Part of me says of course it
> > > is, but a smaller part wants to say the acceleration is
> > > greater at the bottom than at the top. I not sure my
> > > equipment is sensitive to detect those differences.
> >
> > Howdy,
> >
> > It is NOT gravity that causes a pendulum to swing; in the small angle
> > approximation, it's the horizontal component of the tension in the
> > string that makes the pendulum oscillate.
> >
> > Good Luck,
> > --
> > Herb Schulz
> > (herbs@interaccess.com)
>
> I've always found this way of analysing the forces conceptually poor.
> Whether I'm about to use the small angle approximation or not, it seems
> more to the point to consider the pendulum as moving along an arc of a
> circle, with tangential velocity and acceleration components being of
> interest. The tangential acceleration is g*sin(theta). The tension is
> associated with a radial centripetal acceleration, being a radial force.