1. The Nazca and Pacific Plates are spreading relatively fast—at the rate of 14.2 cm (5.6 in) per year. The East Pacific Rise is a midocean ridge system that divides these plates. If the central...

1. The Nazca and Pacific Plates are spreading relatively fast—at the rate of 14.2 cm (5.6 in) per year. The East Pacific Rise is a midocean ridge system that divides these plates. If the central segment of the rise is 200 km wide, show that it is about 700,000 years old.

2. A sample of basalt has a mass of 5.6 g and a volume of
 . Show that the density of basalt is 2.8 g/cm³
.