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## Homework Statement

In the ammonia (NH3) molecule of the figure, the three hydrogen (H) atoms form an equilateral triangle, with the center of the triangle at distance

*d*= 9.40 ✕ 10^−11 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 ✕ 10^−11 m.

(a) What is the

*x*coordinate of the molecule's center of mass?

(b) What is the

*y*coordinate of the molecule's center of mass?

## Homework Equations

x_cm = sum of (m*x)/M

(same for y)

## The Attempt at a Solution

(a) I'm not quite sure how to deal with the two hydrogens towards the negative x-axis — they're not exactly on the axis at all.

(b) None of the H's have any y values, so I did 13.9*sqrt(L^2-d^2)/(13.9+3*1) where 3*1 accounted for the masses of the three H's, but apparently that answer is wrong, and I've no idea why it is. (I got 1.137*10^-(10).)