[MissDee]

A Potassium Bromide molecule consists of a Potassium atom having mass m_K = 39.1 amu, and a Bromine atom having mass mBr = 79.9 amu.

The separation of the two atoms in the molecule is 2.82 [Å].
(Note: [Å] represents the angstrom unit of length and is equivalent to 10-10 [m] ).

How far is the center-of-mass of the KBr molecule from the Br atom?

[MOTOBALL]

And you cannot solve this because...

[Jorriss]

I'll give you some hints.

Define what you're measuring relative too - Center of mass is a relative property. It's probably easiest to say the center of your coordinate system is the center of the molecule.

Next, take the formula for Center of mass. In this case, you only need to consider one direction, so the formula is:

(m1x1+m2x2)/(m1+m2), where x1 and x2 are the positions of the nuclei relative to the center of the molecule.

I don't know if you've taken introductory physics yet so my explanation here is loose.

[MissDee]

This helps a lot, thank you!

I'll give you some hints.

Define what you're measuring relative too - Center of mass is a relative property. It's probably easiest to say the center of your coordinate system is the center of the molecule.

Next, take the formula for Center of mass. In this case, you only need to consider one direction, so the formula is:

(m1x1+m2x2)/(m1+m2), where x1 and x2 are the positions of the nuclei relative to the center of the molecule.

I don't know if you've taken introductory physics yet so my explanation here is loose.

[MOTOBALL]

I want to apologize for the sarcasm expressed in my earlier response to your posting.  If you haven't taken any physics, then the solution isn't obvious.

Regards,

Motoball