August 14, 2011

When Vectors Don't Lie

My second son is just about finished with his on-line Honors Geometry course. There are a few differences taking a class on-line vs. in a high school classroom.

1) When you're in HS and they tell you that you're going to cover the book, that's the goal. When you're on-line, you cover the book. They don't care how long you take, you're going to cover ALL the information. It's YOUR time.

2) Instruction on-line is more difficult. My son was fortunate to have a Mom who could teach him anything. As he said to me after going through the lesson, 'OK, Mom, dumb it down for me and tell me what they really want...' The kids do it all the time without in home tutoring, I'm sure, but that's a tough go.

3) The on-line class is much more jacked up. Seriously, I don't think we covered Vectors in Geometry in HS. I know my eldest son didn't. At least I don't remember him covering it. But vectors and finding magnitude and direction... is what led to tonight's post.

I was on the phone with TGOO telling him about the stuff that T was covering. We were trying to remember when we covered vector translation when we were in high school. I'm thinking it was Analytical Geometry my senior year.

And that's when he said, 'Did you see that crane video? What an excellent tool to teach T about vectors...'

TGOO and I were on the phone watching the various videos, laughing in horror at the miscalculations. The company is blaming a computer program; I questioned that until I read that the crane does actually have a computer program inside telling the operator what he can and cannot do.

But what I said to TGOO, is surely the crane came with a manual that said what the max load could be, in particular at various heights. It's not rocket science. Did they ignore it?

So here are two great videos. The first is the crane horror show as its load is exceeded. The second is the crane that is brought in... to save the crane.

Holy crap.

Posted by Boudicca at August 14, 2011 06:05 PM

I watched that first video with knots in my stomach, and by the end, I was laughing and crying at the same time.

A couple years ago, the people I work for were having a hot tub installed at their house. They needed a crane. Somebody didn't do the right math.

Fortunately, it wasn't quite as catastrophic as that video. But by the time everything was done, they had lost a good portion of their newly built deck and newly renovated house. Ouch! But they do now have a very lovely hot tub!

Posted by: DogsDontPurr at August 14, 2011 07:06 PM

Is that nuts or what? And that guy screaming?! Holy crap. Thankfully nobody got hurt!

I was on youtube looking this up to post it and I saw a newscoverage that said the pool got installed shortly thereafter. Similar to what you stated, they may have lost the garage and the chimney, but they have a very lovely pool!

Posted by: Bou at August 14, 2011 07:35 PM

I once had a physics teacher who would use either real-life engineering disasters or make one up similar to what was shown in those videos as class problems. Perhaps a bit morbid, but it kept everybody's attention and made learning physics a lot more fun.

Posted by: diamond dave at August 14, 2011 08:48 PM


Remember that old video they'd show of the bridge collapsing? I think it was showing resonance. I think I was in elementary school when they were first starting to explain Physics. Education was better back then...

Some things you don't forget!

Posted by: bou at August 14, 2011 08:53 PM

Tacoma Narrows 1940. Just down the highway from us.

http://www.type in the name of a popular video host

Posted by: heresolong at August 14, 2011 11:18 PM

I remember the bridge. I loved that video...wonder if I can find it!!!

Posted by: vwbug at August 15, 2011 05:52 AM

There are so many safety warning systems that the engineers have built into those cranes to prevent weights and angles from reaching dangerous levels, that an operators has to actively disable the safety systems, and then disable the system that prevents the crane from lifting if one of the safetys is disabled, in order for that to happen. Not Cool. But a good demonstration of use of vecotrs (math type, not biology type) and physics - dont mess with gravity.

Posted by: Web at August 15, 2011 06:56 AM

Heresolong has a the video and I found it last night after I typed that comment to Dave. It is the Tacoma Narrows bridge. There are a couple videos up, the one I did like was narrated. It talks about how there was a little dog in that car and the Professor tried to rescue it and it bit him, so he left it. The dog died when the bridge finally collapsed.

Posted by: Bou at August 15, 2011 06:58 AM

Web- I didn't know that! They are saying computer malfunction,but after what you said, I'm thinking it was operator error. Good Grief. Who would mess with that?

Posted by: Bou at August 15, 2011 07:00 AM

In every manual for a crane with a computer there is a warning that the computer is an "Aid" and should not be used in place of the load charts which give the max load for the boom length used and the radius from the center pin of the crane. That crane didn't look that old to have a faulty load sensor. It looked like the computer shut down any further booming down when everything stopped when the load got to the rear of the house. Thats probably when the operator turned off the computer and went to "bypass",boomed down some more, and the tip over resulted.

Posted by: gsebes at August 15, 2011 06:59 PM

The accident is interesting because the crane did not tip over until after the load fell. There's a popping sound which I interpret as the computer malfunction. The load goes into free-fall. Then the cable catches and the momentum of the falling load pulls the crane over.

From the video of the crane there's nothing that has come off or broken that would have allowed it to tip over. I don't think this can happen by operator error unless there's some thing you can press that releases the load and then reengages it. And I don't think cranes have that.

Posted by: Carl Brannen at August 18, 2011 04:35 PM