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| bio | website | david.carybros.com |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 2 years, 5 months |
| seen | 2 days ago | |
| stats | profile views | 118 |
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Jun 1 |
suggested | suggested edit on How much energy is in a lightning strike? |
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Dec 25 |
awarded | Yearling |
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Nov 13 |
awarded | Organizer |
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Nov 13 |
revised |
Is a given volume of sparkling water lighter or heavier than the same volume of still water? add tags, etc. |
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Nov 13 |
suggested | suggested edit on Is a given volume of sparkling water lighter or heavier than the same volume of still water? |
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Sep 28 |
awarded | Commentator |
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Sep 28 |
comment |
Graphene space elevator possible? @dmckee: Huh? Yes, putting 100 tons in geostationary orbit is expensive. But it didn't bankrupt the whole planet the last time we put 100 tons (a little at a time) into geostationary orbit. Since humans have already done it once, the evidence seems to indicate that putting 100 tons into geostationary orbit is feasible. |
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Jun 14 |
comment |
A circuit with no voltage difference, but current flowing You're right -- human skin resistance is normally a few orders of magnitude higher. |
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Apr 26 |
answered | A circuit with no voltage difference, but current flowing |
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Apr 22 |
answered | How does the 'water jet pack' work? |
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Apr 3 |
awarded | Editor |
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Apr 3 |
comment |
Can astronomers directly detect black holes? @Frédéric Grosshans: I see that very long line. I think I fixed it ... |
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Apr 3 |
revised |
Can astronomers directly detect black holes? fixed formatting: no longer one super-wide line. (also a few typos). |
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Apr 3 |
suggested | suggested edit on Can astronomers directly detect black holes? |
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Apr 2 |
comment |
Why can different batteries with the same voltage send different currents through the same object? There's a usually unspoken rule of thumb when designing stuff with batteries: The people designing the battery promise they will keep the voltage within a certain range as long as the the current pulled from the battery is less than some maximum current. The people designing other stuff promise to pull less than some maximum current from the battery as long as the voltage applied is in the normal operating range. When these promises are violated, the convenient simple rules of thumb we use ("batteries put out a constant voltage") don't work anymore. |
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Apr 2 |
answered | Is a signal traveling through fiber faster than a signal traveling through copper? |
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Apr 2 |
comment |
Why can different batteries with the same voltage send different currents through the same object? The cold cranking amperes (CCA) rating of a starter battery is defined as the amount of current a battery can deliver while maintaining at least 1.2 V per cell (under certain conditions) -- that is, maintaining at least 7.2 V across the terminals of the battery, which is much less than the 12.6 V fully-charged open-circuit voltage or the 11.9 V fully-discharged open-circuit voltage of the same "12 V" battery. I suspect the actual voltage across that little 12 V during this experiment is much lower. |
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Apr 2 |
comment |
Why can different batteries with the same voltage send different currents through the same object? Ah, so it does have something to do with area -- not the contact area between the wire and the battery terminal, but the internal "wetted area" at the boundary of the solid plates and the liquid electrolyte. I guess this is why "deep cycle" batteries have relatively smooth solid plates (wetted area approximately LxW of the plate), while "starter" batteries have plates "like a sponge" (wetted area many times the LxW of the plate). |
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Mar 20 |
answered | How long would it take for electricity to flow from one terminal to other, via a 1 LY long wire? |
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Mar 20 |
answered | The speed of light also applies for 'distance' materials? |
