Mathematics · the experiment
Wall in the fire
The fire spreads at speed 1, your wall grows at speed λ. Find the article's thresholds yourself, from the simplest count to the closed loop.
1 · Count the free edge
Beginner
In the article's first argument, where does the fire advance freely?
Set the wall speed. Find the highest one at which this count still guarantees that the fire escapes.
2 · At 1.6 times the fire
Intermediate
Your team lays 1.6 km of wall while the fire advances 1 km. What does the article guarantee?
3 · A single loop
Intermediate
The fire spreads at 3 km/h. Your wall will be one single closed loop. How much wall must you lay per hour, at least?
The last brick goes at the tip, farthest from the fire. Stretch the loop until it needs 2.2 times the fire's speed or less. Lengths in radii of the starting fire.
4 · Walls built to delay
Expert
A team announces a strategy at 1.9 times the fire's speed. None of its walls ends up with fire on both sides. What do you say?
Thresholds found
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