If the density of a piece of wood and the density of water are exactly the same, how much of the piece of wood remains above the water if it has a thickness of 5cm?
To determine how much of the piece of wood remains above the water if its density is the same as that of water, we need to consider the principle of buoyancy. According to Archimedes' principle, an object will float in a fluid if it displaces an amount of fluid equal to its own weight.
In this case, since the density of wood and water are exactly the same, the wood will be neutrally buoyant and will neither sink nor rise. Therefore, the entire thickness of 5 cm will remain above the water.
To understand why, let's consider that the density of water is approximately 1 gram per cubic centimeter (g/cm³). If the density of the wood is also 1 g/cm³, it means that 1 cm³ of wood weighs 1 gram, which is equal to the weight of 1 cm³ of water.
Since wood and water have the same density, the wood will displace an equal volume of water as its own volume. This means that for every cubic centimeter of wood submerged, it will displace an equivalent cubic centimeter of water, ensuring that the wooden piece remains at the same level as the water surface. Therefore, the entire thickness of 5 cm will remain above the water.