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Nov
3
awarded  Revival
Oct
23
revised What causes ballpoint pens to write intermittently?
added 791 characters in body
Oct
12
comment What instrument should I use to vary the power given to a heating element?
@Sara: There are various ways, but those are electrical engineering questions. This is the physics site.
Oct
12
comment The role of mass in the tablecloth trick
@bhaus: I expect with the lightweight plastic plate that air motion affects were significant. With more weight, boundary layer air affects will matter less.
Oct
12
comment What instrument should I use to vary the power given to a heating element?
@What: The OP specified power control, not temperature control, so temperature feedback wouldn't actually solve the problem. Agreed though that the question is thin on specifics. Maybe he does want temperature control, but for now I'm answering what was asked.
Oct
12
comment What instrument should I use to vary the power given to a heating element?
This is the PHYSICS site. Nothing practical here. You want practical, you need the ENGINEERING site.
Oct
12
comment The role of mass in the tablecloth trick
@Carl: Yes, and that's because the classical ridgid body friction is proportional to perpendicular force rule fails. With a napkin on a tablecloth, you have deformable rough surfaces at the macro level, which is nothing like rigid body friction. Dishes and silverware on a reasonably smooth table cloth approximate to rigid body friction well enough for practical purposes.
Oct
12
answered The role of mass in the tablecloth trick
Oct
12
answered What instrument should I use to vary the power given to a heating element?
Oct
4
answered Piezoelectric water flow detection
Sep
28
awarded  forces
Sep
27
comment Which factors are stopping us from studying Titan?
Such a big universe, so little time.
Sep
27
awarded  Nice Answer
Sep
26
answered How does voltage divided by EMF show efficiency?
Sep
25
comment How does an electric field come inside a conducting wire inside the circuit?
@mili: I'm not really sure what to add. A inner chunk of wire can only see the voltage immediately across it. For there to be a voltage across its outer edge, the wire material on the other side of that edge must be conducting, else there would be no voltage by Ohm's law. One layer has to conduct before the next layer has a voltage drop across it, which then causes it to conduct. In reality there aren't discrete layers, so it is actually a exponential decay of the full current propagating into the interior of the wire.
Sep
11
awarded  Civic Duty
Sep
4
comment Can I electrify a pin by applying current in its base?
Closing because cross-posting is not appreciated: engineering.stackexchange.com/q/5296/624
Aug
16
answered Is it possible to calculate the dimensions of ANY object in a picture having at some known distance an object on know dimensions?
Aug
2
comment Can a hybrid vehicle ever be more efficient than a hydrocarbon-only vehicle built with the same parts?
@Chris: I don't believe that most of the energy goes into brakes, at least not for anything other than stop-and-go city driving. Regenerative breaking and shutting down the engine instead of idling certainly help, and hybrids do them for that reason. However, none of these explain why hybrids get such good milage on the highway. Even hybrids like the Toyota Prius and the Honda Civis Hybrid still do better on the highway than in city driving.
Jul
28
comment Why it is colder in mountains, at high altitudes?
Whoever downvoted this, it would be useful to know what you think is incorrect, misleading, or badly written.