Homework Help: Mass of particules

1. Mar 3, 2013

Cerdocyon

Hello,
The problem is quite simple.
Estimate the mass of particules that contains the earth's magnetosphere up to a distance of 100 times erath's radius (In the shadow cone of earth) and also up to the break point or stopping point of the side of the sun.The solar activity is at its minimum and the average density is 10 protons/cm³.
Thank you.

2. Mar 3, 2013

Staff: Mentor

This looks like homework. What did you do so far?
Where did you run into problems?

3. Mar 3, 2013

Cerdocyon

Well indeed it's a homework and i didn't get anywhere i can't figure out how to calculate the mass of particules.

4. Mar 3, 2013

Staff: Mentor

You have a particle density. Do you know the mass of a proton?
Do you know some relation between density in a volume and total mass? What do you need for that?

5. Mar 3, 2013

Cerdocyon

Well, the mass of a proton is 1.67*10^-27 and i know that density equals volume divided by mass but i don't have a volume and i certainly don't see a way how to calculate it and furthermore there are distances which i don't knowwhat will be the use of them.

6. Mar 3, 2013

Mordred

The volume you need is described. First look up the radius of the Earth. Multiply that by 100. Then use geometry to calculate the volume. If areas are excluded work out the volume of the excluded regions
and subtract those from the total volume. Your given the average density so it should be easy from there