Answer:
28,400 N
Explanation:
Let's start by calculating the pressure that acts on the upper surface of the hatch. It is given by the sum of the atmospheric pressure and the pressure due to the columb of water, which is given by Stevin's law:

On the lower part of the hatch, there is a pressure equal to

So, the net pressure acting on the hatch is

which acts from above.
The area of the hatch is given by:

So, the force needed to open the hatch from the inside is equal to the pressure multiplied by the area of the hatch:

Please elaborate more on your question so I can help you
<span>For a point mass the moment of inertia is just
the mass times the square of perpendicular distance to the rotation axis, I =
mr^2. That point mass relationship becomes the basis for all other moments of
inertia since any object can be built up from a collection of point masses. So the
I = (1.2 kg)(0.66m/2)^2 = 0.1307 kg m2</span>