ASTR220 Hamilton Homework #2 (12 points) due Wednesday Mar. 4 at the beginning of class If you are late to class (within 10 min.), be sure to look for the TA and turn your homework in to him immediately. Two points will be deducted for late homework. The penalty will increase the later you are and no homework will be accepted after corrected papers are returned. QUESTION 1. Visit the ASTR 220 homepage http://www.astro.umd.edu/~hamilton/ASTR220/ using Netscape. Find out the latest information on Spacewatch. What is the purpose and procedure of Spacewatch? What are some of their results? How are they funded? Be sure to reference any www sites used. QUESTION 2. Check out the "Working with Equations" link from the class web page and make sure that you understand how to do the problems. You will need to do similar calculations for QUESTION 3. Tell me, in a sentence or two, whether or not you are comfortable with equations and whether this web tool was useful to you. The page has never before been seen by students, so any suggestions for improving it would be appreciated! QUESTION 3. It is estimated that the body (asteroid) whose impact formed Meteor Crater, AZ was about 60 meters in diameter and its composition was most similar to an iron meteorite. Its velocity is estimated at 20 km/s. This impact formed a crater 1.2 km (0.75 miles) in diameter. For each of a-c, first use the kinetic energy equation (1/2 m v^2) to predict how the energy of motion of the impactor would be affected by the given change (i.e. increase/decrease by a factor of X -- find X). More energy means a bigger crater. (Only simple calculations are necessary; use table on Handout #5 and the "Working with Equations" link on the web page to help you.) Then check your answer by modeling each impact on the "Collisions with Planets" link from the class web page. Write down the amount of energy released in each impact, and the diameter of the resulting crater. a) what if the velocity was 60 km/s (instead of 20 km/s) b) what if the asteroid was 120 meters in diameter (instead of 60 meters) c) what if it was a comet nucleus of density 0.75 grams per cubic cm (rather than an iron asteroid of density 7.5 grams per cubic cm). QUESTION 4. Explain how the observations made by the Alvarez team led to a new theory accounting for the K/T mass extinctions. (Be sure to discuss the observations and describe the theory.) QUESTION 5. Explain why a new theory for the formation of the Moon was necessary after the Apollo landings. (Discuss the observations made and describe the theory.) EXTRA CREDIT is available on this assignment -- see the "Extra Credit Assignments" part of the class web page.