Search found 7 matches

by michelcolman
Tue Sep 06, 2011 1:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0947: “Investing”
Replies: 148
Views: 34991

Re: 0947: “Investing”

OK, he fixed it. The comic says "1219" now.
by michelcolman
Tue Sep 06, 2011 10:09 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0947: “Investing”
Replies: 148
Views: 34991

Re: 0947: “Investing”

If you compound continuously (which I believe most banks do, you use the formula (principal) * exp(annual rate * number of years), which I calculate coming out to $1,221 for this example...still lower than the comic says. Banks in Europe (at least in Belgium) only pay interest once a year (although...
by michelcolman
Sun Nov 07, 2010 10:44 am UTC
Forum: Mathematics
Topic: What shape are these?
Replies: 3
Views: 768

Re: What shape are these?

I haven't double-checked the numbers, but if the relative position of the lines is as you described, I would describe the first shape as "a plane with a disc removed" and the second as a "one-sheeted hyperboloid" (which is the mathematical name of the hourglass shape, since you c...
by michelcolman
Sat Oct 09, 2010 12:32 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 102221

Re: 0803: "Airfoil"

A little (imprecise) experiment to demonstrate the coanda effect and lift (or diffusers on race cars). Turn on your tap and dangle the backside (convex) of a spoon near it. Slowly move the spoon into the stream. When the spoon meets the stream it will be pulled further into the stream by the reacti...
by michelcolman
Sat Oct 09, 2010 12:09 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 102221

Re: 0803: "Airfoil"

You realized this in middle school? Most adults answer this riddle wrong: You take a lump of gold, get into a boat on a closed lake and row a bit. Then you throw the gold into the water. Does the water level of the lake sink or rise? Or this one, which my physics teacher got wrong: What happens to ...
by michelcolman
Sat Oct 09, 2010 11:57 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 102221

Re: 0803: "Airfoil"

jpers36 wrote:
Karilyn wrote:FYI: You count to 100 on two hands using one thumb as a 5, and the other hand having fingers be 10 with the thumb being 50.

9 on the 100 scale looks the same as 5 on the traditional finger counting scale.


Forget that, I can count to 1024 on my two hands.

How do you represent zero then?
by michelcolman
Fri Oct 08, 2010 10:32 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 102221

Re: 0803: "Airfoil"

I'm an airline pilot, and I was fed exactly this theory (equal transit time, Bernoulli) during ATPL airline pilot theoretical training. It is amazingly common, and I would guess at least 90% of pilots believe it to be true because it's all they were ever taught. Whenever this theory is given to a cl...

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