The thickness of the ice layer on the surface of lake is 20 m. A hole is made in the ice layer. What is the minimum length of the rope required to take a bucket full of water out? (Take density of ice = 0.9×103kg/m3)

Given that density of ice = 910×density of water, so only 110th of ice will be outside the water. This means that 20 ×110 =2m of ice layer will be above the water surface. In other words, in the hole, the water level with rise up to 18 m of the ice layer. So minimum length of rope required = 2 m.