11.6 Surfaces in Space 691
____ 15. Some planet is an oblate ellipsoid rather than a sphere because of the forces caused
by its rotation. The equatorial radius of this planet is 4961 miles and the polar radius is 4687 miles.
Find the equation of the ellipsoid. (Assume that the center of a planet is at the origin and that the trace
formed by the plane corresponds to the equator.)
a.
b.
c.
d.
e.
____ 16. The top of a rubber bushing designed to absorb vibrations in an automobile is the
surface of revolution generated by revolving the curve in the yz-plane about
the z-axis. Find an equation for the surface of revolution.
a.
b.
c.
d.
e.
____ 17. The top of a rubber bushing designed to absorb vibrations in an automobile is the
surface of revolution generated by revolving the curve in the yz-plane about
the z-axis. All measurements are in centimeters and the bushing is set on the xy-plane. Use the shell
method to find its volume. Round your answer to one decimal place.
a.
b.
c.
d.
e.