284 reputation
19
bio website
location United States
age 48
visits member for 3 years, 11 months
seen Nov 3 at 15:33

whatever.


Nov
3
comment Is energy expended when a force is exerted on a object?
no work is done on the object -- which is not the same as saying that which exerts the force does not dissipate energy.
Sep
24
awarded  Autobiographer
Jun
6
awarded  Popular Question
Sep
27
comment Why do car keys have longer range when held next to your head?
RF key fobs are typically only somewhere around 300 to 500MHz, for which the wavelength is 1m down to 60cm. Even at 2.45GHz, common for lots of things but not afaik, key fobs, wavelength is ~ 12cm.
Dec
3
awarded  Yearling
Sep
29
awarded  Citizen Patrol
Sep
29
comment What is the relationship between AC frequency, volts, amps and watts?
hit 'flag' like I just did. A mod will come and see these comments and that ought to do it, I'm pretty sure they have an easy button.
Sep
26
comment What is the relationship between AC frequency, volts, amps and watts?
might be better served on electronics.stackexchange.com
Sep
19
comment How to find the poles on a spherical magnet?
the torque being proportional to the sine of the angle is problematic, though, in that it wouldn't take much to influence where the equilibrium point lands. the plate should be smooth, as should the magnet, to reduce any kind of friction that would prevent rolling. Any kind of field in the plate would hugely skew the result.
Sep
19
comment How to find the poles on a spherical magnet?
assume the sphere is in contact at some point other than where the flux density is max (i.e., the pole). The distribution of the field around that contact point will be asymmetric. In particular, the region of maximal flux density should attract the plate more than other points at the same angle away from the contact point. Most of this force would be upward, but there would be a slight tangential component (going as sine of the angle of contact-center-pole) that should torque the sphere so as to roll until the pole produces no such torque, as happens when the poll IS the point of contact.
Sep
18
answered How to find the poles on a spherical magnet?
Sep
1
answered Why does current alternate in an AC generator?
Jun
19
comment Is fire matter or energy?
fission, fusion, and ordinary combustion ('fire') are all processes.
Jun
19
comment Is fire matter or energy?
+1 just on the basis of naming it for what it is, a process.
May
18
accepted stability of hypothetical lunar atmosphere
May
8
comment stability of hypothetical lunar atmosphere
@anna v - i've heard it said that the atmosphere of Mars is so thin, b/c that body doesn't have enough magnetosphere to keep the solar wind from interacting with the topmost reaches of its atmosphere. Presumably this effect would be more pronounced on the moon, w/weaker gravity still. I have no idea how one calculates the effect.
May
8
comment stability of hypothetical lunar atmosphere
just wondering whether it'd be days or millenia.
May
8
asked stability of hypothetical lunar atmosphere
Apr
28
comment What is the mathematical nature of space time quantization in string theory/super string theory?
string theory doesn't achieve quantization of space. string theory is 'background dependent', a description of how things happen IN space, taking the pre-existence of some kind of space as a given. much effort in string theory is spent arguing the shape and dimensions of that space. perhaps you are thinking of loop quantum gravity, a background independent view (like GR), which seems to take quantization of space itself as a starting point.
Mar
6
comment Cosmic ray hazards
so .. basically, the secondary particles produced from the initial collision are themselves high energy particles, and the vast majority of the particle shower simply keeps on going, through the astronaut, and out the other side?