A piece of wood has a density less than that of water. What will happen when it is placed in water?

• A. It will sink to the bottom.
• B. It will dissolve in the water.
• C. It will remain suspended in the middle of the water.
• D. It will float on the surface.

Answer: (D)

Verified step by step guidance

1. Recall the definition of density: density is mass per unit volume, given by the formula \(\rho = \frac{m}{V}\), where \(\rho\) is density, \(m\) is mass, and \(V\) is volume.
2. Understand that whether an object sinks or floats in a fluid depends on the relative densities of the object and the fluid. If the object's density is less than the fluid's density, it will float; if greater, it will sink.
3. Since the piece of wood has a density less than that of water, it means the wood is less dense than water, so it will experience a buoyant force greater than its weight when placed in water.
4. The buoyant force is the upward force exerted by the fluid, which can be calculated using Archimedes' principle: \(F_b = \rho_{fluid} \times V_{displaced} \times g\), where \(\rho_{fluid}\) is the density of the fluid, \(V_{displaced}\) is the volume of fluid displaced, and \(g\) is acceleration due to gravity.
5. Because the wood is less dense, it will displace a volume of water equal to its own weight before being fully submerged, causing it to float on the surface rather than sink or remain suspended.