Find the volume generated by rotating the given region about the specified line.
R1 about x = 0.
![2382_volume generated by rotating the given region.png](https://secure.tutorsglobe.com/CMSImages/2382_volume%20generated%20by%20rotating%20the%20given%20region.png)
A manufacturer drills a hole through the center of a metal sphere of radius R = 4. The hole has a radius r. What value of r will produce a ring whose volume is exactly half the volume of the sphere?