I was expecting something a little different, where they passed on him because he didn't give the 'right' answer (what the interviewer had preconceived and/or looked up online).
I feel like most jobs get boring in a year or less. Usually it's due to the bureaucracy and not having any input into the business systems that were implement in the tech.
I'm fairly certain a square manhole cover with a sufficient perimeter would still have no chance of falling into a hole, depending on the diameter of said hole.
It explains in the joke how it's possible to fit a square cover into a slightly smaller square hole. The easiest way is to position the cover vertically and across the diagonal. The lip that the square cover rests on would have to be impractically large to fully prevent the cover from fitting into the hole.
Right, but this makes the area of the cover twice the area of the hole, and the cover twice as heavy as it would need to be if it were round. As Feynman pointed out, even round covers are already pretty heavy—I injured my wrist (ligaments?) from the tension of lifting one in my teens.
However, if this were the only consideration, you could get a wider-diameter manhole with a smaller cover by making it in the form of an equilateral triangle, as evidently Nashua, NH, does: https://en.wikipedia.org/wiki/Manhole_cover#Other. Indeed, you don't need to stop there; if you curve the sides of the triangle in toward the center, you can get a manhole with an even smaller surface area for a given diameter, although at some point the extra "diameter" will be too curved to be useful.
Indeed, though to do it this way would be very wasteful of resources as the ratio of the manhole size to the size of the cover wouldn't be maximized. The cover would be needlessly covering a lip whose large size only exists because of the poor choice of shape.
This is almost certainly the answer. They're round to fit the cylindrical holes they're covering, and those holes are round because they're made with drills, and they're made with drills because that's a lot faster and cheaper than digging.
Pretty sure I can toss a triangular cover into a triangular hole. You might be thinking of a Reuleaux triangle (which is not a triangle, narrowly conceived.)
Let's just say there are many questions that people ask in interviews where they have a scientific sounding answer that is simple and wrong (when considered in full context).
it's not your job to consider it in full context and give the globally true answer (as feynmann attempted here). it's your job to be cleverer than the interview, perceive what they want to hear, and tell it back to them in a way that maximizes the score they give you on the interview.
The reason you do that is it directly impacts the size of the job offer they give you if you answer questions exactly the way you want to hear. It's eminently rational, and a form of social engineering. Once you're hired you can advocate for change from within *
* I tried to get google to change many of it's stupidest hiring practices for years but it was tilting at a windmill
This has nothing to do with full context and some obscure scientific fact. The squared manholes are super common. Many of them are squared and I probably stepped over some squared on my way to interview.
It is like asking why milk is sold always in yellow box. The question makes no sense, because milk boxes can have any color.
