I really shouldnt be stuck on those problems but for whatever reason i cant solve them(adsbygoogle = window.adsbygoogle || []).push({});

Problem: A particular spherical cloud of gas of radius 3 km is more dense at

the center than towards the edge. The density, D, of the gas at a distance p km

from the center is given by [tex]D(p) = 9 - p^2[/tex]. Write an integral representing the total mass of the cloud of gas, and evaluate it.

Solution: density = mass/area. The spherical cloud's area is 9pi/2

mass =9/2 pi (9-p^2).

So mass = [tex]\frac{9pi}{2} \int_{0}^{pi} \int_{0}^{3} (9-r^2) \ r \ dr \ dtheta [/tex]

Is this correct?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Ok another few problems

**Physics Forums | Science Articles, Homework Help, Discussion**