Answer:
Assuming h as the height of the cylindrical tank
[tex]F=480\pi h \,g\,\, \frac{lb}{ft}[/tex]
Explanation:
Assuming that the height is [tex]h[/tex] we can find the volume of the cylindrical tank, then:
[tex]V=\pi*r^2*h[/tex]
The diameter is 8.00 ft then [tex]r=4.00 ft[/tex] the total volume of the tank is:
[tex]V=\pi (4.00 ft)^2 h=16\pi h\,\, ft^2[/tex]
But the tank is half full of oil, then we need half of the volume. For that reason the volume of oil is:
[tex]V_{oil}=\frac{16\pi h}{2}ft^2=8\pi h \,\,ft^2[/tex]
We know the density of the oil [tex]\rho=60.0\,lb/ft^3[/tex], with this we can fing the mass of oil that we have because:
[tex]\rho=\frac{m}{V}[/tex] then [tex]m=\rho V[/tex]
Then the mass of oil that we have is:
[tex]m=(60.0\frac{lb}{ft^3})(8\pi h\,\,ft^2)[/tex]
[tex]m=480\pi h \frac{lb}{ft}[/tex]
Note that with the value of h we have the mass in correct units.
Finally to find the force we now that [tex]F=mg[/tex] then we just need to multiply the mass by the gravity.
[tex]F=480\pi h \,g\,\, \frac{lb}{ft}[/tex]