Geography 121, Global Physical Environment Problem Set 3

Please make sure to show all work. When you compose your assignment, make sure to re-type the problem questions before starting your calculations. Work can be submitted as a Microsoft Word or PDF document (as long as appropriate work is included). Feel free to scan your work prior to sending in the assignment.

1. If the Pacific plate moves northwest at the rate of 1.5 feet in 12 years, what is the rate in centimeters per year? Please express your answer to one decimal place accuracy.

2. Volcanic glass cools very rapidly when expelled at the same time as a volcanic eruption. These rocks have very small crystals, and assume crystal growth is a function of distance from the volcanic cone. If 5,000 volcanic glass crystals form for every five feet of distance above the cone, how many crystals have formed when the rock is 100 feet above the cone?

3. A pyroclastic flow races down a mountainside at 125 miles per hour. Express this velocity in meters per second. In addition, if an observer is 8 kilometers away from the summit where the pyroclastic flow emanated, how much time (seconds) will elapse before the sightseer is overtaken by the incandescent material? Please express your answers to one decimal place accuracy.

4. Volcanic cinders are ejected from a volcanic crater at 200 miles per hour. Please convert this velocity to: 1) meters per second; and, 2) kilometers per hour. Please express your answers to one decimal place accuracy.

5. The temperature of lava flanking a volcano is 500° F. Convert this temperature to degrees Celsius. Please express your answer to one decimal place accuracy.