Volume of a sphere with a cylindrical hole

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SUMMARY

The volume of a solid formed by drilling a cylindrical hole through the center of a sphere is determined solely by the length L of the hole, independent of the sphere's radius. This conclusion can be reached using the method of cylindrical shells, specifically by revolving the shaded area around the x-axis. The discussion emphasizes that the radius of the sphere does not affect the final volume calculation, which is a critical insight for solving related problems in calculus.

PREREQUISITES
  • Understanding of volume calculations in calculus
  • Familiarity with the method of cylindrical shells
  • Knowledge of solid of revolution concepts
  • Basic geometry of spheres and cylinders
NEXT STEPS
  • Study the method of cylindrical shells in detail
  • Explore problems involving solids of revolution
  • Learn how to derive volume formulas for composite solids
  • Investigate the relationship between dimensions and volume in geometric shapes
USEFUL FOR

Students studying calculus, particularly those focusing on volume calculations and geometric applications, as well as educators seeking to enhance their teaching of solid geometry concepts.

dhphysics
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Hello all,

I am doing homework and have come upon this question:
A cylindrical hole is drilled all the way through the center of a sphere (as shown in the figure below). Show that the volume of the remaining solid depends only on the length L of the hole, not on the size of the sphere.
Figure:
Screen Shot 2015-08-30 at 2.25.22 PM.png


I think the problem should be solved using cylindrical shells, but I'm not sure how I should start it. Can anyone give me a hint?

Thanks
 
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dhphysics said:
Hello all,

I am doing homework and have come upon this question:
A cylindrical hole is drilled all the way through the center of a sphere (as shown in the figure below). Show that the volume of the remaining solid depends only on the length L of the hole, not on the size of the sphere.
Figure:
View attachment 88013

I think the problem should be solved using cylindrical shells, but I'm not sure how I should start it. Can anyone give me a hint?

Thanks
If this is homework, in future, please fill out the Homework template and post it in the relevant HW forum.

[Note: I've moved this thread to the Calculus HW forum for you.]
 
Hello dhph,

How about if you try to find the volume of such a bead by revolving the shaded area around the x-axis ? Good chance R drops out !

upload_2015-8-31_0-8-24.png
 

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