1. If the Atlantic sea floor is spreading at 3.0 cm/yr and is now 6400 km wide, how long ago were the continents in contact? How does that time span compare to the age of the Earth?
2. The smallest detail visible through Earth-based telescopes is about 1 arcsec in diameter. What linear size is this on the Moon? (Use the small-angle formula)
1. If the Atlantic sea floor is spreading at 3.0 cm/yr and is now 6400 km...