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Challenge Question

01/13/2012 8:28 AM

Challenge Question stolen from CarTalk. Please don't play if you've heard it.

A young Electrical Engineer visits his aging Granddad on his farm up-state. While there, the young man volunteers to help the old guy in his daily chores. That morning, they hike up the hill behind the barn to chop wood. On the way, the old man stops at the barn, dons a pair of work gloves and picks up an old, rusted railroad pry bar. At about four and a half feet long, the bar looked to weigh about forty pounds so the young man offered to carry it up the hill.

At the top of the hill they find an old Model T Ford truck with no tires perched up on two long logs running across the frame, one near each axel. Behind the truck are an equally old hydraulic log splitter and a large pile of seasoned logs cut for splitting. Between the two is a long leather belt looped around the pulley on the hydraulic pump and the left rear wheel rim.

The old man starts the truck with surprising ease and leans back grinning at the sound of a well maintained engine. He then retrieves the railroad bar from his grandson and drives it into the ground behind the truck and leans forward, rolling the truck on the logs and tightening the old leather belt, thus starting the pump on the log splitter. With a final and well practiced jerk, he wedges the bar under the lip of the bed rail to hold it in place while they work.

The wood is well seasoned and light for its size. The morning is cool with a slight breeze. The two men work together in silence, both appreciating the quiet company of the other. In just two hours they split the coming week's worth of fire wood. Usually, the old man offers, he would be up here for four or five hours accomplishing the same task by himself. As thanks, he offers his grandson a cup of coffee back at the farmhouse. As they prepare to go, the Grandfather leans over with one hand and pulls the pry bar from under the lip at the back of the truck, allowing it to roll back and release the tension on the old leather drive belt. Then, after reaching in and killing engine on the truck, both men walk back down the hill together taking turns with the heavy pry bar.

After spending a long satisfying weekend with his granddad, the young man flies back to the city. Some weeks later, while surveying one of his projects in the field he sees one of the workers using a long pry bar with a fiberglass lever arm. The entire thing weighs just eight pounds. He excitedly asks about it and finds out where he can get one for himself. The next day he ships a long box containing the gift to the old man he loves and admires so much.

Two weeks later the young man receives a phone call, the town Sherriff is offering his condolences. The old man has had a heart attack. Although he had many friends in town, the young engineer is the only living relative. The funeral would be in three days. Devastated, the grandson books a flight out the following day. He doesn't sleep at all that night. He cries and he laughs at the memories of that fine, if obstinate, old man. In the morning he is still sad and hollow, but infinitely thankful for the time that he was allowed with his grandfather.

The day before the funeral friends gather at the farmhouse. The young man, dressed in a black button down shirt and denim jeans, is surprised at how many people show up and the stories they tell. They tell stories about the generosity of the old man and his unceasing willingness to help; about how he was a longstanding pillar of the community with an unwavering sense of justice and fairness. All of them are happy to finally meet the grandson they had heard so much about.

The town Sherriff introduces himself and again offers his condolences. The young man asks how it happened and did his granddad suffer? The Sherriff tells him the town Doctor said it was quick. They had found him at the top of the hill behind the barn, lying next to his old truck and a large pile of freshly split wood. The young man tells the Sherriff the story of the last time he was at the farm and the work he had shared with his granddad. He talks about the gift he had sent just a few weeks back and how he hoped that he had eased the old guy's burden before he died.

Just what kind of work, the Sherriff wanted to know, did the boy do back in the city? The young man indicated that he was an Electrical Engineer and that it was his grandfather who paid for his education. "He'd have been better off if you were an accountant. You should have known better, son. Turn around, you're under arrest."

Why?

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Guru
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#1

Re: Challenge Question

01/13/2012 8:47 AM

Fiberglass is an insulator. The metal bar is a path to ground for the static charge built up by the leather belt while it is running.

The truck is up on wooden logs, so it is no longer grounded unless that metal bar is jammed between the truck body and the ground.

The fiberglass, being an insulator, allowed a huge charge to build up on the truck (Van de Graaff generator) and when the work was done the man tried to turn off the engine, but received a fatal shock.

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#2

Re: Challenge Question

01/13/2012 8:52 AM

Static from the leather Zap him. The old steel pry bar had been ground.

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#3
In reply to #1

Re: Challenge Question

01/13/2012 9:02 AM

Bravo... thats why in India we have lemon hanging with the vehicle touching ground.

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#4
In reply to #1

Re: Challenge Question

01/13/2012 9:37 AM

"you're under arrest..." I'm surprised the sheriff put all that together so quick, or maybe he was a former engineer? Anyways, at least, there wasn't a bloddy mess.

But I wander if the energy stored could have been enough to cook the man, I have seen burns produced by the ionized gas chamber of an industrial laser marker (You charge two plates above 50KV and then produce an arc) and painful as they were, they were not lethal for the poor guy.

I know, I know, the path thru you heart an all that, but the duration of the current plays an important roll when it comes to frying someone, just ask those executed on the electric chair... Oh OK they can't speak anymore, but many, many of them needed several discharges to flush their bodies from their sinful souls... which reminds me the old man was known for being obstinate, maybe he kept trying ? Oh well, that I'll never know.

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Guru

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#5

Re: Challenge Question

01/13/2012 9:45 AM

While I've never heard of anybody dying from electrostatic discharge directly, a healthy person that is, it could cause the death of somebody with a pacemaker....If the old man had a pacemaker, and the kid knew about it, then there would be grounds to charge him...

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#6
In reply to #1

Re: Challenge Question

01/13/2012 10:15 AM

Wow, you nailed it on the first post to the last detail. Even the exact event that killed him.

Folks, I know this was a bit old and obviously too easy but, I really miss challenge questions like this. Even the one about helium ballons in a car as it turns was more fun than what we have seen lately. Or maybe I've just been missing all the good ones. Or, maybe I'm just not smart enough to enjoy the questions that have been comming down the pipe lately.

-A-

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#7
In reply to #5

Re: Challenge Question

01/13/2012 10:17 AM

"grounds to charge him..."

te he.

-A-

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#8
In reply to #1

Re: Challenge Question

01/13/2012 6:11 PM

GA

But I doubt given the dielectric strength of wood, the outdoor situation, leather on iron, would produce much of a charge.

The bigger puzzle is 'how does the wood get down the hill'?

I.e. where is the pickup that would avoid carrying of the bar anyway?

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#9

Re: Challenge Question

01/14/2012 6:08 AM

I don't necessarily see the point of arresting the guy; his mistake may have been naive rather than intentional. (Even if it is just a story.)

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#10
In reply to #9

Re: Challenge Question

01/14/2012 9:47 AM

It is intended as another "clue" to the challenge, not to connect it with reality.

It was designed to link "electrical engineer" to the puzzle and that the cause was something under that domain of knowledge.

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#11
In reply to #8

Re: Challenge Question

01/16/2012 8:24 AM

I agree there is only a small chance of something like this ever actually happening. Moisture in the wood should have been enough to keep the charge below fatal levels. However, the clue about the wood being light for it's size suggests low humidity and very dry logs. How much of a charge could have been built up versus how much it would have taken to kill the old guy is up for debate. Obviously, if we are to take the story as being true, it was enough.

All this being said, is the "bigger puzzel" how the wood got down the hill? Do you inagine the cop and the doctor standing next to the body of the old man scratching there heads and saying, "Van De Graaff, sure! But, look at all this WOOD!"

-A-

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#12
In reply to #11

Re: Challenge Question

01/16/2012 7:10 PM

"Do you imagine the cop and the doctor standing next to the body of the old man scratching there heads and saying, "Van De Graaff, sure! But, look at all this WOOD!""

No, more like "So where is the truck granddad would have driven up to take the wood back down?"

It's quite conceivable granddad took advantage of the young muscle on hand and just walked it on that first day. But to be up splitting more infers a need for more wood. So unless there is a conveyor of some sort, or it's not a 'chore' but a business, how does he get the wood down or where does it go?

Perhaps a truck thief or dispute with a customer caused the heart attack?

Then again, adopting prosecutor hat; the kid made the whole walking story up.

The Sheriff rightly knows no one goes out getting wood without a means of getting it back and secondly, the rusty old bar would be so, as it lives up the hill, not in the barn, as no one bothers with storing rusty bars as all they do eat hands and gloves.

The absence of truck at the scene then clearly indicates the kid used it to bring the the old bar down to put in the barn, along with the inverter he hooked to the truck battery to provide the current required for a fatal shock.

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