4. A 25.0-kg child is running down a hill with a velocity of 6.50 m/s. What is her
momentum?

sure im new too!

explanation:

level 4 to level 2 : ))

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.