A block of wood floats on water. A layer of oil is now poured on top of

Question:

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, as shown in FIGURE 15-43.

(a) Is the volume of wood submerged in water greater than, less than, or the same as before?
(b) If 90% of the wood is submerged in water before the oil is added, find the fraction submerged when oil with a density of 875 kg/m3 covers the block?