Volumes of solids of revolution

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SUMMARY

The discussion focuses on calculating the volume of a solid formed by boring a cylinder through a sphere. The sphere has a radius of 'a', while the cylinder has a radius of 'a/2'. The recommended approach involves setting the sphere in a three-dimensional coordinate system and using the function f(x) = sqrt((a^2)/4 - x^2) to represent the curve of the sphere. By rotating this function around the y-axis and integrating from 0 to a/4, one can determine the volume of the cylinder within the sphere, which is essential for finding the remaining solid's volume.

PREREQUISITES
  • Understanding of solid geometry and volumes of revolution
  • Familiarity with integral calculus and volume integration techniques
  • Knowledge of coordinate systems in three-dimensional space
  • Ability to work with functions and their rotations
NEXT STEPS
  • Study the method of cylindrical shells for volume calculations
  • Learn about the disk method for finding volumes of solids of revolution
  • Explore the concept of triple integrals in three-dimensional calculus
  • Investigate the properties of spheres and cylinders in geometry
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Students studying calculus, particularly those focusing on volumes of solids of revolution, as well as educators and tutors seeking to clarify geometric volume concepts.

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Homework Statement


A circle with a radius of (a/2) is bored through the centre of a sphere of radius a. Find the volume of the remaining solid.


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The Attempt at a Solution


I've been trying this for an hour now and I've been trying to find the remaining volume by finding the area of the cylinder bored + the little side bits on each side. I've just been getting really messy answers which aren't close to the actual answer.

Urgently need a hand :)
 
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The easiest way to do this is in my opinion:
Set the sphere in the center of an xyz-axis system with the axis of the cilinder the y-axis. (for example)
Now consider just the first quadrant in the xy-axis system.
You should know that you can make a function of the curve you see ( f(x)= sqrt( (a^2)/4 - x^2 ) )

To find the volume of the cylinder inside the sphere you only have to rotate the function around the y-axis while integrating from 0 to a/4. Multiply by two and you have the total volume of the cylinder within the sphere.

I'm sure you will be able to solve it now ;).
Goodluck
 
Last edited:

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