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If Richard Feynman applied for a job at Microsoft
Saturday, August 20, 2005 7:36 PM
| Interviewer: |
Now comes the part of the interview where we ask a question to test your creative thinking ability. Don't think too hard about it, just apply everyday common sense, and describe your reasoning process.
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Here's the question: Why are manhole covers round?
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| Feynman: |
They're not. Some manhole covers are square. It's true that there are SOME round ones, but I've seen square ones, and rectangular ones.
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| Interviewer: |
But just considering the round ones, why are they round?
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| Feynman: |
If we are just considering the round ones, then they are round by definition. That statement is a tautology.
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| Interviewer: |
I mean, why are there round ones at all? Is there some particular value to having round ones?
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| Feynman: |
Yes. Round covers are used when the hole they are covering up is also round. It's simplest to cover a round hole with a round cover.
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| Interviewer: |
Can you think of a property of round covers that gives them an advantage over square ones?
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| Feynman: |
We have to look at what is under the cover to answer that question.
The hole below the over is round because a cylinder is the strongest shape against the compression of the earth around it. Also, the term "manhole" implies a passage big enough for a man, and a human being climbing down a ladder is roughly circular in cross-section. So a cylindrical pipe is the natural shape for manholes. The covers are simply the shape needed to cover up a cylinder.
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| Interviewer: |
Do you believe there is a safety issue? I mean, couldn't square covers fall into the hole and hurt someone?
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| Feynman: |
Not likely. Square covers are sometimes used on prefabricated vaults where the access passage is also square. The cover is larger than the passage, and sits on a ledge that supports it along the entire perimeter. The covers are usually made of solid metal and are very heavy. Let's assume a two-foot square opening and a ledge width of 1-1/2 inches. In order to get it to fall in, you would have to lift one side of the cover, then rotate it 30 degrees so that the cover would clear the ledge, and then tilt the cover up nearly 45 degrees from horizontal before the center of gravity would shift enough for it to fall in.
Yes, it's possible, but very unlikely. The people authorized to open manhole covers could easily be trained to do it safely. Applying common engineering sense, the shape of a manhole cover is entirely determined by the shape of the opening it is intended to cover.
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| Interviewer (troubled): |
Excuse me a moment; I have to discuss something with my management team. (Leaves room.)
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(Interviewer returns after 10 minutes)
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| Interviewer: |
We are going to recommend you for immediate hiring into the marketing department.
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![Rated Excellent [5 out of 5].](/Themes/default/images/Star5.gif)
Sick again, with a new sore throat.
Sunday, May 01, 2005 9:40 PM
I had to go back to my doctor again. I hate to be on medication. Antibiotics especially, the part that you've to remember to take them every X hours, and complete the course. I actually don't mind them, especially since they are supposed to help me get well.
So I abstained from all the taboos and toxic such as fried, oily, heaty stuffs. I stayed so clean off alcohol the whole of last week. I was pathetically sipping juice while my friends get their beer and alcohol. I so deserve to get well right? Then just last morning, I woke up with a new sore throat. Maybe it's also the weather. I am so frustrated. *coughs*
Urgh.
Edit: I just ate Tim Tams (Sharon got for me all è way from Melbourne) and I feel so good now.
Heineken Innovation
Wednesday, April 13, 2005 4:16 PM
Here, the Heineken event I was talking about. I'll just blog in pictures. In fact, I think I should just blog in pictures from now on, even though now I have all the time in the world. Too lazy to pull words together..
First Blog Entry
Monday, March 28, 2005 6:36 PM
So, I'm on theSpoke.
When I told some colleagues that I'm on Spoke, some thought I meant that I'm gonna be parta theSpoke Project. Well, I'm just gonna be blogging.
More to come.
Good Friday to y'all.
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