Deriving the volume of the inside of a sphere using spherical coordinates
Using a volume integral and spherical coordinates, we derive the formula of the volume of the inside of a sphere, the volume of a ball.
volume
Just a minute: why do large and heavy ships not sink?
Until they do due to a mistake, ships do not sink, not even the large and heavy ones. Now and then, textbooks say this is because of dissimilar density. Though not a a wrong statement, it is also not a fundamental one. While ships may sink to the bottom of the ocean thanks to gravity, they also float thanks to gravity.