Re: [Phys-L] apparent weight

[brian whatcott <betwys1@sbcglobal.net>]

The thread on the semi diurnal variability of g raised by Anthony was 
quite animated. It needs only a mention of the twice daily change of 
force per mass: corresponding to about 10 mg for a 100 kg mass  - a 
little beyond the resolution offered by the usual scale.

Brian Whatcott    Altus OK

On 12/10/2014 10:11 AM, David Bowman wrote:
> A) Any possible solar tidal effect will be essentially the same at midnight as at noon (to leading order in the multipole expansion, i.e. ignoring higher order multiple effects).  Any diurnal solar tidal discrepancy will be maximum between either midnight/midday and either sunrise/sunset.
> B) The lunar tidal effect is about 2.5 times stronger than the solar one.
>
> David Bowman
>
> -----Original Message-----
> From: Phys-l [mailto:phys-l-bounces@www.phys-l.org] On Behalf Of Anthony Lapinski
> Sent: Wednesday, December 10, 2014 8:04 AM
> To: phys-l@phys-l.org
> Subject: [Phys-L] apparent weight
>
> If you stand on a sensitive scale, will you be slightly lighter at noon (with the Sun above you and pulling opposite to Earth's gravity), and slightly heavier at midnight (with the Sun below you and pulling in the same direction as Earth's gravity)? Ignore any lunar effects.
>
> This came up the other day, and nobody could really agree. One side said no because the Earth is in freefall around the Sun, and it is the Earth that pulls us to it. The other side said yes due to tidal effects as seen in the oceans.
>
> I searched online, and found the same conflicting arguments!
>
> Can anyone help with this?
>
> _______________________________________________
> Forum for Physics Educators
> Phys-l@www.phys-l.org
> http://www.phys-l.org/mailman/listinfo/phys-l
> _______________________________________________
> Forum for Physics Educators
> Phys-l@www.phys-l.org
> http://www.phys-l.org/mailman/listinfo/phys-l