Help with calculating the density of a planet

[gk636]

Question: "Given the mass and radius of the planet Mercury, calculate the density."

 

Mass: 3.3010 x 10 to the 23rd kg

 

Radius: 2.440 x 10 t0 the 6th m

[Endy0816]

What you will want to do for these kinds of problems is to first locate the formulas you need.

ie.

Density = Mass / Volume

 

Now we see Mass is there, but we have a new problem. We don't know volume, so we go searching again:

 

Volume of a Sphere = 4/3 * Pi * r^3

 

or taken together:

 

Density = Mass / (4/3 * Pi * r^3)

From there you can plug your knowns(Mass, radius) in to find your unknowns(Density).