Halliday, Resnick & Walker — Center of Mass and Linear Momentum: Problem 7

7 In the ammonia (NH3) molecule of Fig. 9-29, three hydrogen (H) atoms form an equilateral triangle, with the center of the triangle at distance $d = 9.40 \times 10^{-11} \text{ m}$ from each hydrogen atom. The nitrogen (N) atom is at the apex of a pyramid, with the three hydrogen atoms forming the base. The nitrogen-to-hydrogen atomic mass ratio is $13.9$, and the nitrogen-to-hydrogen distance is $L = 10.14 \times 10^{-11} \text{ m}$. What are the (a) $x$ and (b) $y$ coordinates of the molecule’s center of mass?