Very dumb classic mechanics question here: The other day I caught sight of a trivial objects arrangement: a basketball placed on top of a 6-sided cardboard box on the floor, and I wondered how the weight of the hollowed sphere could cause bending on the supported, flat top surface of the box. However, despite having studied physics in undergrad, I could not work out the mechanisms involved: 1) Could time be a contributing factor to the bending (i.e, the box gradually cave in over time) or if the surface fails to bend at t0, it won't ever bend? 2) does bending depend on the top surface area of the box, e.g., whether increasing/decreasing the top surface area 100x while maintaining the same four sides would make a difference? 3) how does the material (e.g., rigidity) and weight of either the basketball (~700g) or the cardboard box factor into the their opposing forces and latter's bending? Any intuition or explanatory equation is much appreciated!