ANSWERS TO Q 1 – 5 BELOW
Posts Tagged ‘2025’
25 Amazing Numbers for 2025 … Q 6 – 10
January 10, 2026Correction:
It was 43°C (109.4°F) in Melbourne when Mathspig was writing the post!!! I used the wrong heading – now corrected -when it was first published.
The Maximum temperature recorded for Melbourne was 46.4°C (115.5°F) in 2009.
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ANSWERS TO Q 6 – 10 BELOW
AMAZING ANSWERS
Why Wild Fires Go Wild . . USA UNITS
January 11, 2025Tragic Wildfires are still burning in LA on 11th JAN 2025 with
HOW FAST IS A GRASS FIRE?
This, of course, depends on the wind speed.
Grass fire Speed in Australia on a flat land
= 12mph – 20mph (in a gentle breeze.)
CAN YOU OUT RUN A FIRE?
Average Running Speed Boy 13–14 yo = 10 ft/sec = 6.8 mph
Average Running Speed Girl 13–14 yo = 8 ft/sec = 5.5 mph
Usain Bolt Speed on the Flat = 27.78 mph
Usain Bolt could out run a grass fire on a flat surface.
But 13 yos would be in trouble.
See more Firefighters Need Maths here.
NOW YOU ARE RUNNING UP HILL. WHAT HAPPENS?
We’ll assume, due to being motivated by having a fire licking your heels, that you can run at your top speed up hill for a short time, at least. But here is the problem.
The Chimney Effect
Heat rises and so there is a Chimney Effect pushing the fire uphill. The rule of thumb used by fire fighters is:
Each 10º increase in slope, the fire front speed doubles.
Slope 0º = 12 mph
Slope 10º = 24 mph
Slope 20º = 48 mph
Slope 30º = 96 mph
Slope 40º = 192 mph
The steeper the slope the harder it is to run fast and the faster the fire front moves.
Your survival will depend how far away you are from the fire front when you start running.
Again we can do very accurate calculations using simultaneous equations. See Firefighters Need Maths here.
CAN YOU OUT RUN A WILD FIRE?
High winds can turn a bush or forrest fire into a WILD FIRE with wind gusts up to 240 mph and temperatures up to 2000 °C, which can and does melt glass and cars.
The fire front speed doubles with every 10º, so speeds for the fire front in a strong wind can reach 140 mph, 210 mph and up to 280 mph.
One Smoke Jumper survived an uphill wild fire. Read the amzing story
Mathspig Blog 