A cylindrical tank of internal diameter 1.5m and length 2.0m is mounted on a trailer. When the tank is filled with water the combined weight is 55 kN. Find the weight of tank plus trailer with the tank full of methyl alcohol (relative density 0.789).
pi*r²*length= volume of cylindre
The Attempt at a Solution
total volume of methyl in tank= 3.53 m³
using density of methyl (789 kg/m³)
mass of methyl in tank= 2788.55 kg
however, I don't see how this is gonna help finding the mass of water in the tank filled with water or the mass of the tank. Basically, if I don't find the volume of water in the tank filled but not fully with water I cannot find the mass of that water. Therefore, I cannot find the mass of the tank and trailer.
if anybody could help that would be nice.