Download Physics 121 - Test 1: Moon Phases and Motion Diagrams - Prof. James J. Griffin and more Exams Physics in PDF only on Docsity! Name: โโโโโโโโโโโโโโโโโโ Section: Physics 121โ Test 1 14 October 1992, 12:00-12:50 p.m. Do all eight problems in any order. Write your name on every page, write your answers on the test paper. Scratch work which will not be graded may be done on the backs of the test pages. No notes or calculators may be used during the exam. Theories of the Moon's Phases The next two questions relate to the two most popular theories proposed in class for the phases of the Moon. They are the Earth Shadow (ES) theory and the ViewPoint (VP) theory, and can be briefly stated as follows: The fact that protions of the Moon are dark in a regular "monthly" cycle can be explained (ES) as resulting from a shadow cast by the Earth covering part of the moon at certain times of the month. (VP) as resulting from our limited view of the Moon from our base on Earth. Although sunlight falls on the half of the Moon facing the Sun, on any given day a different half may face Earth including only a portion of the sunlit side of the Moon. Problem 1. Model configurations. On each of the two diagrams below labelled (ES) and (VP) add a circle representing the Moon positioned relative to Earth and Sun (distances not to scale) in the direction required by the corresponding theory to produce a "half moon" view from Earth (i.e., half the Moon is seen dark, half light). n u ^ /, -7 โ> Name: Problem 2. Comparison with reported observation. Suppose that your lab partner recalls seeing a half moon last week. He reports that just as the Sun was setting in the West, he saw a half moon directly South and about 45 deg above the horizon. The bright half of the Moon faced directly toward the horizon in this report, as summarized in the sketch below. '- "-โ If this report could be confirmed as accurate and regular (recurs on a monthly cycle), what consequences would it have for each theory: (ES) Is this reported observation consistent with the Earth Shadow theory? [Yes/No] _________ Explain why: (VP) Is this reported observation consistent with the ViewPoint theory? [Yes/No] ________ Explain why: Qualitative Kinematics Problem 3. Velocities in a motion diagram. A tram on a roller coaster (or a ball on a track) moves from left to right on hills as suggested by the diagram to the right. It starts at the top on the left and continues over the top to the right. Supply velocity vectors in the diaยญ gram for positions A, B, and C, giving the correct directions and giving magnitudes in proper relation to each other. Assume that friction is negligible.
