Buoyancy of wood block problem help

AI Thread Summary
To solve the buoyancy problem involving a wood block floating on water and covered by oil, start by recognizing that the submerged volume of the block is influenced by the densities of both the water and the oil. The initial condition shows that 91% of the block is submerged in water, which can be used to calculate the buoyant force. When oil is added, its density (883 kg/m3) must be considered alongside the buoyant force from both the water and the air. A free body diagram can help visualize the forces acting on the block, including the weight of the block and the buoyant forces. Analyzing these forces will lead to determining the new fraction of the block submerged when the oil is present.
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A block of wood floats on water. A layer of oil is now poured on top of the water to a depth that more than covers the block. If 91% of the wood is submerged in water before the oil is added, find the fraction submerged when oil with a density of 883 kg/m3 covers the block. (Do not neglect the buoyant force of air before the oil is added.)

I would just like help on getting started on this problem. I looked at the equation Vsub=Vs(p,s/p,f) but I wasn't sure how/what values to substitute if they are given as percentages. I tried setting up the equation as 0.91=p,s/p,f but I wasn't sure what I would be solving for/plugging in if I had done that.
 
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Perhaps drawing a free body diagram for analysing the block of wood should help. You should find that there are four forces acting. You can also find the weight of the wooden block from the initial situation.
 

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