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, as shown in Fig. 1, 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, as shown in Fig. 2, 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.

Many readers from all over the world successfully cracked our November Challenge, Ride goes before the fall, including several first-time student contributors hailing from the same school. We are pleased to recognize the following successful solvers

Guidelines for contributors

Many thanks to all contributors and we hope to...

AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.