Re: [Phys-l] How did Newton estimate the Gravitational constant?

[Bernard Cleyet <bernardcleyet@redshift.com>]

This implies a rather high dissipation cf. a gold monofilament.

There's another possible complication.  W/ monof.  the torsion constant is due to (largely) shear elasticity;  w/ the film  it's due to shortening, i.e. the pendulum rises on twisting.  This may not be a linear effect,  therefore, the change in period method of measurement may not be valid.


bc realizes his memory for managing this expt. is from 20 years ago.

p.s. Originally this expt. taught patience.  One person acted as secty, another a timer and the third read off the position of the spot on the two meter stick.  It was purposely not damped, so much data can be collected.  Then the high tech entered by fitting to a multi-factor non-linear least square app.  Often a fit was bad, because of an idiopathic momentary vibration.  Recovery was often successful by breaking into two fits.

When we performed the expt. (more of a demo) at the NPS, I recorded the spot and transferred to VHS because I had (still have) a single/ multiple frame (field?) step player.  The Sony recorder included a clock in 1/100ths sec, which made it even more useful.


On 2010, Oct 29, , at 05:37, Dan L. MacIsaac wrote:

> and videotape quite successfully overcame the endless spinning relaxation you must endure with twine or monofilament.