Question

an army tank weighing more than 100 tans moves conventionaly even on the earthern rod explain？how？

Answer 1

This is because that massive 100tonnes of mass is distributed throughout the body/chassis of the tank. Due to which the weight of the tank is distributed evenly throughout its body. Also you might have noticed the typical wheels of a tank. They are not like those four wheeler vehicles you see. At a particular instant of time more wheels are are in contact with the road surface. It therefore distributes the weight of the tank into a larger area, thereby reducing the intensity of pressure on the road.

Its the same concept behind a sharp knife and a blunted knife you see