[Phys-l] Separating inertial mass and g mass. Was: Re: a different kind of math background quiz

[Bernard Cleyet <bernardcleyet@redshift.com>]

Speaking of:   You all know the mass of a simple pendulum's bob (a physical also) serves both as an inertial mass, as in a spring oscillator, and also as a gravitational mass (a non-linear spring).  Since Eötvös, they are the same.  However, they are not the same if the pendulum is not so simple.  I mean when the bob is immersed in a fluid.  A minor matter if the bob is in air (Horologists, correctly disagree.), but always a serious matter if the fluid is water.  Pray tell, how does one write the diff. eq. to make the correction.  I've done this, and its solution disagrees w/ the horological lit.   Perhaps I've done it correctly and the horological correction is an approximation or I'm too maths challenged to convert.

bc




On 2009, Dec 31, , at 13:37, John Clement wrote:

> The use of weight is inappropriate
> and should be "massing" to try to separate weight from mass, and the
> magnitudes display a lack of understanding of simple metric units as the
> masses are a bit too large for typical objects.