Is pressure from surface on cylinder = weight of cylinder when in water?

Question

Written here are net forces acting on a body. But I am having difficulty in understand them after reading from textbook and online material.
In the book, we have been introduced to thrust.
It clearly says that pressure exerted by a body on the surface = weight of the body.
Then, why is it not that $mg$ is nothing but $P_1A$ and $P_2A$?
Can we also say that it is $F = ma$ expression (the first equation as a whole) where $a = 0$?

MarianD · Accepted Answer

It clearly says that pressure exerted by a body on the surface = weight of the body.

It is simply impossible — their units are different: $left[N over m^2right]$ vs.  $[N]$.
Your book says something other - thrust, not pressure.
The picture is about forces and their difference. There are

2 forces in the top-to-down direction (the gravitational force and the force caused by the water pressure)
1 force in the down-to-top (the force caused by the water pressure).

So the first two forces are added together and the last force is subtracted from their sum.
The resulting force must be a zero force, because the cylinder is not moving.

Is pressure from surface on cylinder = weight of cylinder when in water?

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