Answer:
Assuming h as the height of the cylindrical tank

Step-by-step explanation:
Assuming that the height is
we can find the volume of the cylindrical tank, then:

The diameter is 8.00 ft then
the total volume of the tank is:

But the tank is half full of oil, then we need half of the volume. For that reason the volume of oil is:

We know the density of the oil
, with this we can fing the mass of oil that we have because:
then

Then the mass of oil that we have is:


Note that with the value of h we have the mass in correct units.
Finally to find the force we now that
then we just need to multiply the mass by the gravity.
