(1) Under the condition of equal pressure, if the skier wears a sled on his feet and the stress area is large, according to p=FS, we can know that the pressure acting on the snow is small, and the contact area between the skier and the snow surface is large, so the pressure is small and he will not sink in.

(2) Assuming that the playground area is s,

The pressure of snow on the ground f = g = mg = ρ snowshg; ;

Then the pressure of snow on the ground: p = fs = ρ snowshgs = ρ snowgh;

Therefore, p=ρ Xue GH = 0.2×103kg/m3×10n/kg× 0.05m =100pa.

(3) The sanitation department sprinkles industrial salt on the snowy road surface. When snow is mixed with salt, sand and furnace ash, its melting point will be reduced, which will make snow melt faster. The road surface is snowy and slippery, which is prone to traffic accidents. Installing snow chains on wheels will increase the roughness of contact surfaces, thus increasing the friction between wheels and the ground.

Answer: (1) Under the condition of equal pressure, skiers wear sledges on their feet, and the stress area is large. According to p=FS, the pressure on snow is small, and the contact area between skiers and snow surface is large, so the pressure is small and they will not sink in.

(2) The pressure of snow on the playground is 280 Pa. ..

(3) Sprinkle salt, sand and ash on the snow surface, install snow chains on wheels, shovel snow in time, etc.