posted by physics .
which ons is stronger 1)A solid cylinder of 2)A hollow cylinser of iron 3) A cylinder made up of slits of iron
1) 2 what? How big is the cylinder?
2) how big is the cylinder? How hollow?
3) What are "slits" of iron?
Two types of failure need to be consdered when dealing with cylnders in compression: one is compressive fractyre and the other is buckling.
These are college level topics that I would not expect to be taught in 11th grade. I cannot make any sense out of your question.