Archive for the ‘Computer Program’ Category

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Maths will build a bridge, hopefully!!!!!

February 1, 2012

Engineers need maths.

They (hopefully) calculate stresses and loads on structures BEFORE the building, bridge, airport is built.

Not only do you need maths, mathspigs, to ‘virtually’ destroy the Millenium Bridge in a Harry Potter film, you need maths, obviously, to build the real bridge. Unfortunately, the engineers made a big Boo Boo! They didn’t allow for pedestrian feedback causing sway or wobble. See 10 Biggest Maths Disasters in the World

Here is what happened to the Millennium Bridge

Vibration of the London Millenium Footbridge Maths

Here’s a little grab of the maths showing the pedestrian feedback loop causes wobble.

‘ we see that phase of the pedestrians’ feedback force is leading the output displacement of the bridge deck by an angle which becomes exactly  at the resonant frequency . This of course is what we expect for a negative damping force.’


Lego engineers need maths. 

Lego bridges can be VERY strong.

This is a LEGO MILLENIUM BRIDGE.

But this is NOT a suspension bridge. It is just a model. Here is a FANTASTIC site @ EXPLAIN THAT STUFF showing how bridges work.

A REAL Lego suspension bridge can hold a very heavy load.  Here is a Lego suspension bridge built at LegoWorld 2005. The break load for this Lego bridge was 40kg  (88 lb). This bridge could support a kid.

Here are two other Lego Bridges. The break load for the next bridge was 76 kg (167 lb). The break load for the third bridge was > 100 kg  (220 lb). These bridges could support an average sized adult.

A Neat Lego (Suspension) Bridge on You Tube. *


* Observe neat bridge Vs Unmade bed!

But here is Mathspigs FAV Lego bridge.

Not exactly a suspension bridge but very strong. And this was a kid experiment!!!!!!

Break load = 30.3 kg ( 66.8 lb)

See the next post for some fabulous Lego Maths. In the meantime, if you are going to build a bridge, perhaps, you should do it with maths not love. This is a truly spooky video from Cher and co. Wait for the chorus.


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12 minute Maths Guru

July 4, 2011

Meet Salman Khan. He has put free maths on-line.

This article on Salman appeared in The Sunday Times, UK, 12 JUN 2011.

Salman, 28, started putting tutes online for his 12-year-old niece, Nadia, and things grew. So far the Kahn Academy’s claim to fame are:

* Over 2,400 videos including hundreds and hundreds of 12-minute maths tutes

* Over 63,000,000 lessons delivered.

* Bill Gates kids use the site.

* A staff of 1 with funding from The Bill and Melinda Gates Foundation.

* Tutes on Biology, Chemistry and Physics too.

You can look up the maths tutes by topic @ The Khan Academy.

Or search topics on Youtube eg. Introduction to Conics Khan

Why Does Mathspig like The Kahn Academy? Because it’s:

1. Free.

2. Quick

3. Clear

4. Low-key

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Salman gives digital chalk-and-talk tutes like a teacher. He hand draws the equations and graphs. He uses a calculator from time to time, but he tends not to use whizz bang spreadsheet graphs or perfectly presented textbook equations. It’s a bit wobbly and it’s all coming from Salman’s head.

And students like this approach. It makes maths look do-able.

Go, Salman.

Mathspig thinks you are just GORGEOUS!!!!!!!!!

 Australia’s Year 7 – 12 Maths Curriculum is already on-line and free, funded by McDonald’s. See What are maths teachers for, sir?

The tutes on Maths Online are produced by Aussie Maths teachers and they are very good. Mathspig, of course, imagined the quadratic function tutes might look something like this:


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8 US Patriot Missile Problem:

October 20, 2009

While the debate about the effectiveness of the Patriot Missile in the 1991 Gulf War continues, most observers believe its hit rate was closer to 10 percent than to 90 percent. The failure to stop Scud missiles in one Iraqi missile attack resulted in the death of 28 American soldiers in their barracks in Dhahran, Saudi Arabia.patriot missile 2

The Maths Error: Numbers too Big for the Software Program

In late March 1992, the U.S. General Accounting Office’s report to Congress on the Patriot’s problems was identified as an error in the software, which used the target missile’s velocity and time elapsed to calculate the target position. As the report explained the program was not designed to fit the size of the numbers involved:

patriot missle 1‘Time is kept continuously by the system’s internal clock in tenths of seconds but is expressed as an integer or whole number (e.g., 32, 33, 34 . . .). The longer the system has been running, the larger the number representing time. To predict where the Scud will next appear, both time and velocity must be expressed as real numbers. Because of the way the Patriot computer performs its calculations and the fact that its registers are only 24 bits long, the conversion of time from an integer to a real number cannot be any more precise than 24 bits. This conversion results in a loss of precision causing a less accurate time calculation. The effect of this inaccuracy on the [system’s] calculation is directly proportional to the target’s velocity and the length that the system has been running.’ Consequently, performing the conversion after the Patriot computer system has been running continuously for extended periods causes the [system’s estimated Scud position] to shift away from the center of the target, making it less likely that the target will be successfully intercepted’.gulf war