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sona1177
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Homework Statement
In many locations, such as Lake Washington in Seattle, floating bridges are preferable to conventional bridges. Such a bridge can be constructed out of concrete pontoons, which are essentially concrete boxes filled with air, Styrofoam, or another extremely low-density material. Suppose a floating bridge pontoon is constructed out of concrete and Styrofoam, which have densities of 2200 kg/m3 and 50.0 kg/m3. What must the volume ratio of concrete to Styrofoam be if the pontoon is to float with 34.3% of its overall volume above water?
Homework Equations
Fbuoyancy-mg=o
The Attempt at a Solution
Fbuoy-mg=o
p(fluid)gV(displaced fluid)=p(platoon)g(Vplatoon)
Vfluid/Vplatoon=p(platoon)/p(fluid)=.343
so p(platoon)/p(fluid)=.343
p(plattoon)=p(fluid) *.343
1000 * .343=343 kg/m^3=density of platoon.
Where do i go from here?