Problems
Problems

 1 If a person weighed 200 pounds at the South Pole, what would he or she weigh at the equator? How would the person's mass at the equator compare to his or her mass at the pole? 2 Suppose the history of the Earth were represented by a year. How many days ago would all of the continents have been merged together as the supercontinent Pangaea? At what date and time during the year would the birth of Copernicus have taken place? 3 Geologists have proposed drilling downward through the crust into the mantle. Where should they drill in order to minimize its depth? If they succeed, what percentage of the distance to the center of the Earth will they have drilled? 4 Only about 1/5000 as much energy comes from the interior of the Earth as is absorbed at the surface from sunlight. If no energy reached the Earth from the Sun (or any other celestial object), how would the temperature of the Earth's surface compare to its actual temperature? (To solve this problem, you need to use the Stefan-Boltzmann law, given in Chapter 7.) 5 What fraction of the volume of the Earth is occupied by its core? 6 Near one of the midocean ridges the rock on a strip of ocean bottom shows the same magnetic orientation. The strip is 10 km wide and formed during the period of time between two magnetic reversals that were separated by 200,000 years. How rapidly is the ocean bottom moving with respect to the midocean ridge? 7 Europe and North America are moving apart at 2 cm per year. Find (or estimate) the width of the North Atlantic Ocean and determine how long ago the North Atlantic began to form. 8 How much colder is it likely to be at the top of a 6000- meter mountain than it is at the bottom? 9 Suppose greenhouse gases are introduced into the atmosphere of a planet. The effect of the gases is to cut in half the probability that infrared radiation emitted by the planet can escape into space. What would happen to the amount of infrared energy emitted by the surface of the planet? By approximately what fraction would the temperature of the planet need to increase to bring about the change in the amount of infrared energy emitted? (As in question 4, you need the Stefan- Boltzmann equation to solve this problem.)