Political boundaries are often formed by physical boundaries. An example of this is the Rio Grande River that separates the US from Mexico. An ethnographic boundary or a cultural boundary is a boundary line that runs along differences in ethnicity.
Steel has a density of about 490 pounds per cubic foot, which is more than three times the density of concrete, so the generally accepted density of normally reinforced concrete is 150 pounds per cubic foot which results in a cubic yard weighing 4050 pounds, but this depends on the quantity and grade of the rebar used.
Fresh concrete can weight about 3700 lbs for every cubic yard. The density will also determine how much is its weight. assuming its weight to be around 150 lbs for per cubic f â¦ eet.This would make it around 4000 lbs which could come to 2 tons.resh concrete can weight about 3700 lbs for every cubic yard. The density will also determine how much is its weight. assuming its weight to be around 150 lbs for per cubic f â¦ eet.