Results 1 to 2 of 2

Math Help - Calculating differences in spheres with variable as a radius

  1. #1
    Newbie
    Joined
    Jan 2010
    Posts
    1

    Calculating differences in spheres with variable as a radius

    I'm close to finishing this problem. This isn't strictly a calculus problem, but it seemed closer to one than to a physics problem. I first had to calculate the mass of a sphere inside a sphere. The outside sphere is denser than the inside sphere. Now I need to create a function that represents how a radius r of the inner sphere would change the mass of the sphere. Thanks in advance for any help.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,806
    Thanks
    116
    Quote Originally Posted by djvanthegoat View Post
    I'm close to finishing this problem. This isn't strictly a calculus problem, but it seemed closer to one than to a physics problem. I first had to calculate the mass of a sphere inside a sphere. The outside sphere is denser than the inside sphere. Now I need to create a function that represents how a radius r of the inner sphere would change the mass of the sphere. Thanks in advance for any help.
    Let R denote the radius of the outer sphere and r the radius of the inner sphere. Let d denote the density of the inner sphere and D the density of the surrounding shell that means what is left from the outer sphere. I assume that only the radius of the inner sphere is variable, all other values are constant. Then the mass of the complete solid is calculated by:

    m(r)=\left(\frac43 \pi R^3-\frac43 \pi r^3\right) D + \frac43 \pi r^3 d = \frac43 \pi \left(\left(R^3-r^3\right) D+ r^3 d\right)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Calculating Major & Minor Radius of an Ellipse
    Posted in the Geometry Forum
    Replies: 2
    Last Post: October 9th 2011, 10:41 AM
  2. Calculating radius of a circle from 3 arcs
    Posted in the Geometry Forum
    Replies: 5
    Last Post: June 6th 2011, 06:56 AM
  3. Replies: 12
    Last Post: November 22nd 2009, 04:02 PM
  4. Replies: 1
    Last Post: July 9th 2007, 03:51 AM
  5. Calculating Radius of Spheres
    Posted in the Geometry Forum
    Replies: 1
    Last Post: October 14th 2006, 07:14 AM

Search Tags


/mathhelpforum @mathhelpforum