Chapter 3

A truck loaded with $2{\mathrm{m}}^3$ dry sand appears to weigh " 3 tons" more than the weight of the empty truck. What is the meaning of the term " 3 tons", and what is the volumetric weight of the sand?

The soil in a polder consists of a clay layer of 5 meter thickness, with a porosity of $50\mathrm{\%}$, on top of a deep layer of stiff sand. The water level in the clay is lowered by $1.5$ meter. Experience indicates that then the porosity of the clay is reduced to $40\mathrm{\%}$. What is the subsidence of the soil?

A container is partially filled with water. A scale on the wall indicates that the volume of water is 312 cm3 . The weight of water and container is 568 gram. Some sand is carefully poured into the water. The water level in the container rises to a level that it contains 400 cm3 of material (sand and water). The weight of the container now is 800 gram. Determine the density of the particle material, in kg/m3 .