Question

Compute the force needed on the following shapes to completely submerge them in water for each of these materials: oak of average density, Styrofoam, and hollow aluminum with a 0.5cm wall thickness. A cube 10cm on a side, a cylinder 5cm long and 9cm in diameter, a sphere 15cm in diameter. If the cubes are just placed in water and not forced under how far down into the water does each cube sink? Write what densities you used.

Answer 1

what is your thinking? One never want to get the reputation of an answer moocher.

Answer 2

well wouldn't the force needed to submerge them just be the buoyant force? and to get that all you do is take the density*volume*accerlaration due too gravity

and then i'm not sure exactly how to get how far theym sink. i think it's something to do with net force. which would be the buoyant force minus the weight

Answer 3

right on the first paragraph. For the second, you need to balance the displaced weight of water to equal the weight of the block.

weightwater=weightblock
densitywater*g*l*w*heightsubmerged= density*g*volume*g

Now on the curved surfaces, you have a tricky calculation on the volume of the submerged height.