Yes, when pulsars were discovered many years ago it was at first thought that their puzzleing behaviour might be a sign that they were from some type of intelligent origin. Once there true nature was figured out (as described above by bob) then this belief ceased.
So either that is very very...
Yeah, interseting you should say that Calin. When I was a kid here (in Australia) full sized bike wheels were always listed as 28". I didn't notice when it changed but when I decided to get back into cycling as an adult I suddenly found that 28" was no longer around (not here anyway) and that...
The voltage output from a modified sine wave or PWM inverter don't have voltage spikes that will bother the MOV's of a surge protector. They do however have sharp edges that can cause resonant problems with certain types of passive filters included in some surge protectors.
Whoops I just realised you said 27" circumfrence, sorry I misread the question as 27" diameter (as 27" diameter is actually a very common size of bicycle wheel). For a circumfrence of 27", nails answer was indeed correct.
Ouch, nails calculations are seriously out, he's trying to push those poor ol' folk along at well over 30mph ! The fact is that you require only about 2 revs per second (120 rpm) to attain 10mph.
The roll out diameter of a 27" wheel is about 2.2 meters. Actually it varies a bit depending on...
Yep, i's a useful general way of computing resistance, use nodal analysis to find the terminal voltage due to an impressed 1A current source. It works on active circuits with dependant soucres as well, so you can use it to compute the input and output resistance of amplifiers and other active...
The easiest way to solve that problem is definitely NODAL analysis. You just place a 1 Amp cuurent source between the two diagonally opposite node, take the node at the current source negative as the reference and calculate the voltage a the other node using nodal analysis.
There are7 nodes...
I mentioned this before but I'll say it again. People educated in Science or Mathematical fields are accustomed to dealing with abstracted problems and abstracted meaning of numbers and symbols. If a aerospace scientist grabs a raw data print out of gas pressures and velocities from a wind...
Anyway, it looks like the whole thing is a trick question. Different isotopes often have both physical and chemical properties that are slightly different from each other. In particular I wouldn't mind betting that D2O (heavy water) would have a slightly higher boiling point and correspondingly...
No jai, that 20 is the molecular weight of the entire water molecule (one oxygen plus two deuterium). Anyway look at the new derivation, it's simpler and more accurate. Actually I should have just used 18 as the atomic weight (regular water) in that quoted line. That is actually where the 9/10...
Ok I did make a slightly unjustified approximation with the mass ratio. I took the 0.0156% ratio as the ratio of whole molecules instead of the mass ratio of hydrogen to deuterium as specifically asked. I figured this wouldn't make too much difference and it actually it makes about 11% error (as...
Ok so what answer do you currently hold as correct and from what source did you obtain that answer. Please post the answer you currently have.
Also when you say "wrong", do you mean off by a few percent or are they orders of magnetude (multiples of ten) different. An approx solution is...
Radiation power increases with the fourth power of temperature, so it might be worthwhile to use a heat exchanger (active cooling) between the cpu and the radiator (sink) so that you can operate with a HS temperature somewhat greater than the CPU temperature.
Well I don't know exactly the mass of a gallon so I'll give it to you per liter and you can do the conversion to 7.5 gallons.
There are approx 1000 grams of H2O per Liter, so that gives the equivalent of 0.000156 * 1000 g = 0.156 grams of Deuterium based H2O per Liter. Now each Oxygen atom has...
Yep, there's an absolute value in there, well done. :)
Yeah that was really the point of this challenge, and to show how much more difficult it is when it's not one of the likely candidates (like a linear functional).
Since I'm pretty sure you've got the solution (or something close) and...
Dr P, I think you were somewhat lucky to choose a the correct functional form to try and solve first up.
For example I first tried to solve it using a simple linear functional of the five variables. That is, let x1 be the number showing on the first dice, x2 the number showing on the second...
The "Spam in my InBox" Challenge"
As a follow on from the "Petals around the Rose" challenge in this thread HERE, I have come up with a new but similar challenge. It's called "The Spam in my Inbox" and uses the rolls of 5 dice to unambiguously determine the amount of Spam I have. It is a fairly...
The "Shannon Capacity" is over 500 kbps for each channel.
This theoretical maximum bitrate is given by,
C = W log2(1 + S/N)
Where W is the channel bandwidth and S/N is the power signal to noise ratio.
Working with conservative values of W=20kHz and S/N=80dB (equiv power ratio = 10^8) give...
There is absolutely no reason to assume that the total volume must decrease when the bulge dissappears (as opposed to the volume simply redistributing). That assumption is both unfounded and incorrect.
What about the "spring constant" (elastic modulus) of the earth (rock) itself ? I'm not sure how long it would take to spring back but I've done a very rough calculation that places it somewhere about half an hour, so potentially this bulge would relax perhaps ten times or more quickly than it...
Yes that's correct, DDR-Dual Channel AthlonXP systems have potentially twice the memory bandwidth coming into the Northbrigde than is the link bandwidth from the Northbridge to the CPU. This is definitely a bottleneck situation.
Some people go as far as to say that Dual Channel DDR is...
Ok I just made my program write the results to a text file and immediately discovered a glaringly obvious bug, it had lots of "divide by zeros" allowed. I knew immediately where abouts in the code I had made this mistake so it was easy to fix.
I originally had some code like : "if den<>0 then...
I think you'll find that the energy lost from tidal action slows the Earth and not the Moon ZeroNine8.
Interestingly enough the action of the tides actually serves to increase the Moon's orbital KE rather than reduce it, strange as that might first seem. Here's the reason : As the Earth is...
Interesting results SmoiL. Yeah your results may well be correct and mine wrong. Like I said I only did an extremely quick and nasty job of coding it. Oh well at least this makes it interesting, two different result and neither sure exactly who is correct yet. :)
Just to make it clear of what...
Yeah I know what you're saying SAO, we're looking at slightly different problems. I initially wrote the program simply to test if a given input number had the "24" property. Later I thought it would be kind of interesting to to let it run through every four digit integer (from 0000 through to...
You know, the thing that surprised me when I ran my program was just how many such numbers there actually are. Almost 50% without parentheses and a massive 75% (approx) if parentheses are allowed.
Here is the program output (counts only),
4902 of 10000 without parentheses
7451 of 10000 with...
Interesting SAO, I didn't know that it was a widely used "challange". If that's the case then having a program to generate a list of such numbers would be quite useful, perhaps that was the motivation for this question.
Just out of interest is anyone willing to hazzard a guess about just how...
Quick note: Though I'd avoid parentheses unless explicitly stated in the problem, they would actually be very simple indeed to implement. The above code for operator precedence would be unnecessary and instead you would simply evaluate all six (actually only five are unique) possible oderings of...
Ok Peter, i see your point now. Yes you're still doing three nested loops but your code is more efficient because you're not unnecessarily re-evaluating o1 and o2 on every iteration. So both are correct but yours is more efficient, point well taken!
Yes that's true. Here's a very rough and...
Actually my code is correct Peter. As you earlier noted there are 3^4 operator permutations, and that's exactly what the three nested 4 iteration "for" loops are doing. If you don't nest the "for" loops then you only get 3 x 4 instead of 3^4 combinations, correct! In other words the entire...
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