Integrating Mass of a Hollow Sphere: Multivariable Calculus Explained

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SUMMARY

The discussion focuses on integrating the mass of a hollow sphere using multivariable calculus. Participants emphasize deriving the mass element dM and integrating thin rings that compose the hollow sphere. Two methods are highlighted: one utilizing solid angles and the other without. The reference provided is a valuable resource for visualizing the concepts involved in this integration process.

PREREQUISITES
  • Understanding of multivariable calculus concepts
  • Familiarity with the integration of mass elements
  • Knowledge of solid angles in spherical coordinates
  • Basic principles of mechanics related to hollow spheres
NEXT STEPS
  • Study the derivation of mass elements in spherical coordinates
  • Explore integration techniques for thin rings in three dimensions
  • Learn about solid angles and their applications in physics
  • Review the reference material on hollow spheres from HyperPhysics
USEFUL FOR

Students and educators in physics and mathematics, particularly those studying multivariable calculus and mechanics, will benefit from this discussion.

cwill53
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Homework Statement
I'm just trying to prove that gravitational force on an object within a hollow sphere is zero when these are the only two objects under consideration within the system.
Relevant Equations
$$F_g=G\frac{mM}{r^2}$$
I know some multivariable calculus, I just want someone to walk me through the integration deriving the mass element dM and the integration of thin rings composing the hollow sphere. It would also be nice if you could show me doing it one way using the solid angle and one way without using the solid angle. Thanks.
 
Physics news on Phys.org
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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