TAC blunders energy maths

We see the abuse of science to give legitimacy to a propaganda program in “I swear to tell the truth, part of the truth, the convenient part of the truth”.  The selling of safety in Australia.

But even the mathematics that is presented in the conveniently selected part of the energy argument is wrong.  The Transport Accident Commission (TAC) try to tell motorcyclists that “…travelling at 60 km/h rather than 68 km/h, but he would have around thirty percent less kinetic energy to lose in the event of a crash”.

That’s not right.  Take a 80kg rider on a 200kg bike.  Kinetic Energy = 0.5 x mass (kg) x velocity (m/s) squared

“Fast Rider” KE = 0.5 x 280 x 68 x 68 /(3.6X3.6) = 50.0 kJ

“Slow Rider” KE = 0.5 x 280 x 60 x 60 /(3.6×3.6) = 38.9 kJ

Difference = 11.1kJ

Reduction = 11.1/50.1 = 0.221 = 22%

So when the TAC tell motorcyclist that“he would have around thirty percent less kinetic energy” if it could get the mathematics correct it should say “he would have around twenty percent less kinetic energy”. 

As well only telling the part of the energy story that is convenient the TAC can not even correctly work out the sums on the remaining part.  The information is not credible.  The attempt to use science to bolster a propaganda campaign is a charade.

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About John Culvenor

Hi, Thank you for taking a look at this blog. I work in engineering, ergonomics, creativity, design, training, etc. Often this is about helping solve legal puzzles through accident analysis. Sometimes it is about thinking up better designs for equipment, workplaces, and systems. This blog is about good design and bad design, accident analysis and how it can be done better, and how we can make a better, safer world by design!
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1 Response to TAC blunders energy maths

  1. Pingback: “I swear to tell the truth, part of the truth, the convenient part of the truth”. The selling of safety in Australia. | safedesign

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