The work of Brian mind interface is to learn that’s my guess lol
Mass
The mass of an object attract other objects with mass but, and objet has to have more mass that another object to physically move it
Example
The sun and the earth the sun has a large enough mass to not only make our planet rotate around him but seven more
In metric that means multiplying or dividing by 10, 100, 1000, etc. It consists of a partial word like "kilo" or "milli". For example, the prefix "kilo" means "times a thousand" or " one thousand of" the units in question. So "kilometer" means one thousand meters and "kilogram" means one thousand grams.
If you look at the units of density, g/cm^3 you will see it's grams divided by volume (cm^3).
218.9 g / (0.5*1.55*25 cm^3) = 11.3 g/cm^3