Why is something thicker stronger?

Question

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Answer 1

When long things (beams) bend, they stretch on one side and compress on the other side.  The imaginary plane through the center of the beam does not stretch or bend; it's called the neutral fiber.  The farther things are out from the neutral fiber, the farther they have to stretch or compress when bent.  All things are usually approximated on a small scale like a bunch of springs.  The more you stretch a spring (or anything), the more force you need.  So a thicker object or beam has fibers that must be stretched a greater distance for the same amount of bending as a smaller object.  Not only do the outer fibers have to stretch farther, but there is simply more area in the cross section that needs to be stretched or compressed.  So it's like asking why does it take more force to stretch more springs than less springs.  Basically you are trying to do more work on more mass.