Search found 14 matches

by twcarlson
Mon Apr 29, 2013 1:26 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1205: "Is It Worth the Time?"
Replies: 76
Views: 26530

Re: 1205: "Is It Worth the Time?"

This immediately reminded me of xkcd.com/974/
by twcarlson
Mon Mar 18, 2013 5:24 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1187: "Aspect Ratio"
Replies: 92
Views: 20638

Re: 1187: "Aspect Ratio"

What's worse than the linear stretch of 4:3 to 16:9, is the variable stretch sometimes called "panorama mode" where the sides are stretched and the center stays proportional. This mode has good intentions, but wait until someone or something moves across the screen, accelerating and decele...
by twcarlson
Wed Oct 10, 2012 12:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1119: "Undoing"
Replies: 121
Views: 23653

Re: 1119: "Undoing"

Shouldn't this be a "What-if"? I've always wondered about the effect of wind turbines on the wind. This comic suggests there is less wind, um, downwind of the turbine. Sure, not as much less as is suggested here, but doesn't a huge wind farm have a measurable effect? Wouldn't the same thi...
by twcarlson
Tue Sep 18, 2012 12:55 pm UTC
Forum: What If?
Topic: What-If 0012: "Raindrop"
Replies: 91
Views: 24885

Re: What-if 0012: Raindrop

I calculated the terminal velocity of such a raindrop as 4490 m/s, which is 10,000 mph or mach 13.5. In a vacuum, it would take 7.6 minutes of falling to reach this speed, but in air it would be slower and would approach terminal velocity asymptotically. I got the equation from Wikipedia: t.v. = sqr...
by twcarlson
Wed Sep 12, 2012 8:52 pm UTC
Forum: What If?
Topic: What-If 0011: "Droppings"
Replies: 68
Views: 31173

Re: What-If 0011: Droppings

Although the starting and ending units are in mass of something, that something matters. Perhaps you're right. Do you agree, though, that there is meaning in the tube model of fuel efficiency? In the tube of fuel, miles traveled is the same thing as miles of gasoline, so canceling should be just fi...
by twcarlson
Wed Sep 12, 2012 5:38 pm UTC
Forum: What If?
Topic: What-If 0011: "Droppings"
Replies: 68
Views: 31173

Re: What-If 0011: Droppings

Surprised at his bit about unit conversions. Mostly because it's factually incorrect, and I tend to like him for being right on these things. :( "miles per gallon" is lazy notation we accept in speech. If you want to use it in math, you need to recognize it's "miles traveled per gall...
by twcarlson
Tue Sep 11, 2012 8:57 pm UTC
Forum: What If?
Topic: What-If 0011: "Droppings"
Replies: 68
Views: 31173

Re: What-If 0011: Droppings

I wanted to offer my take on the fuel economy units. The best form to use depends on what you're most interested; in other words, what is fixed and what is variable. In the beginning, people were more concerned about distance . For a given fill-up, how much distance do I get? A car that could get 20...
by twcarlson
Tue Sep 11, 2012 8:55 pm UTC
Forum: What If?
Topic: What-If 0011: "Droppings"
Replies: 68
Views: 31173

Re: What-If 0011: Droppings

> If you took all the gas you burned on a trip and stretched it out into a thin tube along > your route, 0.1 square millimeters would be the cross-sectional area of that tube. It seems to me that is rather close to the cross section of the fuel line actually going from the tank to the engine. Anybo...
by twcarlson
Tue Sep 11, 2012 3:20 pm UTC
Forum: What If?
Topic: What-If 0011: "Droppings"
Replies: 68
Views: 31173

Re: What-If 0011: Droppings

What comes out is, in the case of gasoline, (720 (kg/L)/1.98 (kg/L)^(2/3)*(32+12)u/12u*0.335 mm^2=62 mm^2 of CO2, neglecting the mass contribution of non-carbon atoms in petroleum, and assuming perfect combustion. So really more something like 60 mm^2 of CO2. Imagining a tube of CO 2 around a centi...
by twcarlson
Tue Sep 11, 2012 2:08 pm UTC
Forum: What If?
Topic: What-If 0011: "Droppings"
Replies: 68
Views: 31173

Re: What-If 0011: Droppings

Something doesn't smell right about that last formula. Suppose we double the number of miles driven, to 6 trillion a year. The amount of guano is constant, so one would expect that the efficiency needed in miles per gallon to increase, but if we put it into the formula, we find that it decreases. Y...
by twcarlson
Mon Sep 10, 2012 12:08 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1106: "ADD"
Replies: 121
Views: 30640

Re: 1106: "ADD"

This reminds me of the GTD method by David Allen. Unless you come up with a good system for tying those balloons down until you can deal with them, you'll never be able to fully control the one you're holding now.
by twcarlson
Wed Jul 18, 2012 1:01 pm UTC
Forum: What If?
Topic: What-If 0003: "Yoda"
Replies: 122
Views: 80470

Re: What-If 0003: Yoda

Also I have seen a big mistake in your calculation: 5300 * 0.9 * 1.4 / 3.6 = 1855 W = 1.85 kW (NOT 18.5) You forgot to include "g", which is 9.81 m/s^2. So 5300 * 0.9 * 9.81 * 1.4 / 3.6 = 18197 W = 18.2 kW. Although he uses 18.3 for some reason. It's confusing because the "g" in...
by twcarlson
Tue Apr 10, 2012 4:43 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1040: "Lakes and Oceans"
Replies: 166
Views: 79659

Re: 1040: "Lakes and Oceans"

sorry, but i'm gonna do it... i require clarifaction on 'bike tyre'... Road Bike [100psi]? cross country [~45 PSI]? trail bike [~20 PSI]? :) But a great cartoon, I love the scale chart ones... #hopes for poster# Has to be the road bike tire at a pressure of perhaps 110 psi (7 atms). It's too deep t...
by twcarlson
Tue Apr 10, 2012 1:04 pm UTC
Forum: Serious Business
Topic: Google and Confirmation Bias. Is it time to stop 'googling'?
Replies: 26
Views: 12995

Re: Google and Confirmation Bias. Is it time to stop 'googli

There's a toggle switch on the search results page to switch between personalized results and generic results. In theory, everyone should see the same results then (possibly limited by your SafeSearch filter and the country from which you access the site).

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