Also known as reference frame, it is in dynamics<span>, system of graduated lines symbolically attached to a body that serve to describe the position of points relative to the body.</span>
The mass of aluminium foil is calculated as follows
mass = density x volume
density = 2.70 g/cm^3
volume 54 cm^3
mass of aluminium foil is therefore = 2.70 g/cm^3 x 54 cm^3 =145.8 grams
cm^3 cancel out each other
2.4 x 10²² atoms
<h3>Further explanation</h3>
Atomic mass is the average atomic mass of all its isotopes
In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu
So the atomic mass obtained is the mass of the atom relative to the 12th carbon atom
mass single Uranium atom=4.7 x 10⁻²² g
then for 111 mg=0.111 g

Scientific questions and hypotheses come up frequently while one is engaged in investigating a scientific phenomenon such as natural geological phenomena as may occur in geological mapping in the field. For example, there may be a question does this canyon or deeply incised valley which is quite straight follow a weakness in the earth's crust like a major fault or the direction of bedding in well bedded sedimentary rocks. In a particular topographic area, some hypotheses which may be developed is that valleys follow geological structure whereas ridges follow resistant rocks like quartzites or quartz sandstones or in the ocean, points or capes may represent resistant quartz sandstones and bays may represent weak soft shales recessively weathering