Why are descriptive investigation’s repeatable

Can somebody explain to me how newton's 3rd law relates to momentum? ~ap physics 1

Which type of bond is found between the atoms of a molecule? a. metallic b. delocalized electron c. covalent d. ionic

An ideal polarizer with its transmission axis rotated 30 degrees to the vertical is placed in a beam of unpolarized light of intensity 10w/m^2. after passing through the polarizer, what is the intensity of the beam? a. 8.7 w/m^2 b. 7.5 w/m^2 c. 5.0 w/m^2 d. 10 w/m^2 e. 2.5 w/m^2