Three engineers were asked to design a dam. The cross section of their plans is shown below. Whose plan got approved?
Plan of engineer A.
Plan of engineer B.
Plan of engineer C.
all the plans were rejected

Dear student,

As we know Pressure= height of water column x density of water x gravitational acceleration.
That means with depth , pressure increases.
so, the dam experience more pressure at the bottom than in top,
so the dam must have greater area to sustain more pressure at the bottom side.
In the three plan proposed by the engineers, only in Plan A have suitable structure of dam (with wider bottom to sustain more water pressure).

So, plan A will get approved.

Regards,