Question

The foundation below the beams of a building is much wider than the walls.what could be the reasons.

Answer 1

Imagine the building to be a bag full of water. One would experience the pressure to be maximum at the bottom (according to p=h×rho×g). More the pressure implies greater the stress. Hence the foundation has to be wider to support the building because of it's weight by withstanding enormous stress. We also know that pressure=force/area. greater the area, lesser the pressure.

Note: The corollary with the water filled bag and the building is not the exact answer. It is used here just for explanation. But the concept used is same and thus can be compared.