A square-shaped thin block of ice is floating in a lake. If a load of mass M is carefully placed at the center of the block the top surface of the ice barely stays above the water. What is the maximum load m that can be placed near the midpoint of an edge of the block so that the load would remain above the water? Assume that the load doesn’t slip off the block.

The densities of ice and water are 900 kg/m3 and 1000 kg/m3, respectively.

When the load of mass M is centered on the block of ice and the block is just fully submerged, we have from Newton’s second law,
(1)
where W is the weight of the ice block and B is the buoyant force on the fully submerged block
Now, when the load of mass m...
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