Have you ever eaten Lamian Noodles? In fact, the process of making Lamian Noodles is permeated with mathematical knowledge. A certain volume of dough is made into Lamian Noodles, and the total length y(m) of noodles is (1) According to the image, the inverse proportional function image passes through the point (4, 32),

Let the functional relationship between y and s make y=ks,

K4=32，

The solution is k= 128,

The functional relationship between y and s is y =128s;

(2) When s = 2mm, y =1282 = 64m;

(3)∵y≤40，y= 128s，

∴ 128s≤40，

∴s≥3.2.

That is, if the total length of noodles does not exceed 40m, then the thinnest noodles should be 3.2mm2 。