- #1

rsala

- 40

- 0

## Homework Statement

Pluto's diameter is approximately 2370 km, and the diameter of its satellite Charon is 1250 km Although the distance varies, they are often about 1.99×104 km apart, center-to-center.

Assuming that both Pluto and Charon have the same composition and hence the same average density, find the location of the center of mass of this system relative to the center of Pluto. answer in km.

## Homework Equations

[tex]\frac{\Sigma m*r}{\Sigma m}[/tex]

## The Attempt at a Solution

i didnt know how to approach this problem since i didnt know the masses of the objects, so i treated each unit of kg in its diameter as 1 unit of m, so the mass pluto would be 2370,000*M...? (converted all units to meters, not sure if it matters)

so, since the question asks for center of mass relative to pluto center, i don't include plutos m*r since its initial position is 0.

[tex]\frac{1250,000*M*(1.99*10^{4}*1000)}{2370,000*M + 1250,000*M} [/tex]

i guess m can factor out here.[tex]\frac{1250,000*(1.99*10^{4}*1000)}{2370,000 + 1250,000} [/tex]

this equals 6871547 meters, 6871.5 km

this is incorrect, I don't think this is correct because i just have the feeling that i don't know what I am doing here