# Finding kilograms of water on a spherical planet

1. Aug 25, 2015

### PAstudent

(Moderators note: moved from technical forums, does not use template)

How would someone approach this problem?

Find mass in kg of spherical planet if:
-71.11% of surface is covered by oceans
- avg depth of oceans is 12.83 furlongs
-avg density of water is 1.030 g/mL
-avg radius of planet is 4,895 miles

Last edited by a moderator: Aug 26, 2015
2. Aug 25, 2015

### RUber

Do you have an average density for the non-water part of the planet? Or are you just looking for the mass of water on the spherical planet?

Edit: I see now in the title that you are just looking for the water.

Step 1, draw a picture.
Step 2, find the total volume of the sphere from avg. depth to avg. radius.
Step 3, multiply total volume by % surface that is water.
Step 4, multiply that volume by density to find mass.

3. Aug 25, 2015

### SteamKing

Staff Emeritus
Step 1.5: use consistent units in your calculations.

4. Aug 25, 2015

### RUber

Example:
"convert furlongs to km" returns.
1 furlong = 0.201168 kilometers.

5. Aug 25, 2015

### PAstudent

I got 3.518x10^16 kg. Does that sound reasonable?

Edit: Disregard that I may have found an error in my calculations

Last edited: Aug 25, 2015