Physics20A S02 MIDTERM EXAM - Version D

Physics20A S02 MIDTERM EXAM - Version D - VERSION: D...

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Unformatted text preview: VERSION: D PHYSICS 20A BUOTE MIDTERM EXAM #1 Clear your desk except for a #2 pencil, eraser, calculator, and scantron card Possibly Useful Information: (1) For a right triangle with hypotenuse, d, interior angle, 9, and side, D, opposite to 8, we have the following small-angle formula: 6 (arc sec) 2 206,265? (2) In the Heliocentric Model: _1ii S i P P Earth Gmlm2 d2 (3) Magnitude of Gravitational Force: F = l. The vernal equinoxis now moving into the constellation Aquarius because A. the Moon's orbit is not in exactly the same plane as the ecliptic. B. the Earth processes since its spin axis is not perpindicular C. D. to the ecliptic. it maves through different constellations throughout the year. all ofthe above 2. Who discovered the moons ofJupiter? A. B. C. D. Hipparchus Tycho Brahe Galileo Newton 3. Suppose an object moves in a circular path at constant speed. What can be said about the force acting on it? A. B. C. D. There is no force acting on it. The force acting on it must constantly vary in strength. The force acting on it must vary in direction. The force acting on it must be gravity. 4. In the Copernican Heliocentric model epicycles were introduced primarily to explain the A. B. C. D. retrograde motion of the planets. prograde motion ofthe planets the variation of the speed ofa planet during its orbit. diurnal motion. 3 5. Suppose an astronaut whose mass is 50kg pus hes herself away from an artificial satellite which has a mass of 500 kg. While she is pushing, the acceleration ofthe satellite is 1 rn/s per second. What is the acceleration of the astronaut? A. B C D my». r "norm (a - -' 2i lrn/s per second 10 m/s persecond 1/10 m/s per second 100 m’s per second 6. For an object to accelerate it must one? change its speed. I ‘ change its direction of motion. ' . change its speed and direction of motion. change its speed or direction of motion. 7. The force required to keep an object in a circular orbit is directed one» . away from the center ofthe circle. in the direction in which the object is moving. . in the direction opposite to that in which the object is moving. . toward the center of the circle. Page 1 8. Why was Tycho unwilling to acetept that the stars are too far away for himto be able to detect their parallaxes? 10. 11. 12. 13. 14. A. He thought he could measure the angular diameters of stars. B. He assumed the Earth was stationary. C. He knew Saturn was at the same distance as the stars. D. Trick question, he could, in fact, measure stellar parallaxes. . How will an object move if there are no forces acting on it? A. with constant acceleration B. in a straight line at constant speed C. on an ellipse D. it can't move at all ifno forces are present Which ofthe following bodies is accelerating? A. a body moving in a straight line at constant speed B. a body at rest C. a body moving in a circle at constant speed D. a body with no forces acting on it The circular orbit of a planet in the Ptolernaic model distinct from the planet's motion about the Earth is called A. . a deferent. B. an epicycle. C. the seconday orbit. D. the synodic orbit. According to Kepler's laws, a planet moves fastest in its orbit when it is A. nearest the Earth in the Earth's orbital plane. B. nearestthe Sun. C. midway between the foci ofits orbit. D. farthest from the ecliptic. When a planet moves westward with respect to the stars it is said to undergo what kind ofmotion‘? A. prograde B. retrograde __ C. diurnal 54""- D. epicyclic Which ofthe following is NOT true about Galileo: A. His discovery of the Moons of Jupiter showed that the Earth was not the center of all motion in the universe. B. His discovery ofrnountains and valleys on the Moon and spots on the Sun dismissed the idea ofa perfect heavenly realm He confirmed Tycho's naked—eye measurements of the angular diameters of the stars. . He noticed that the Sun, Moon. and the planets looked bigger when viewed through the telescope. we Page 2 15. 16. 18. 19. 20. 21. 17. The proportionality between the square of the siderialperiod and the cube ofthe semi-major axis of a planet's orbit was discoved by A. Copernicus. B. Kepler. C. Galileo. D. Newton. An object speeds up in such a way that its acceleration is constant. What can we say about the force acting on the object? A. There is no force acting on it. B. The force acting on it is constant. C. The force acting on it increases steadily. D. The force acting on it decreases steadily. Kepler's 2nd Law states that the product of the transverse speed and the distance from the Sun is constant along the planet‘s orbit. Consequently, ifthe ratio of aphelion to perihelion distance is 2, what is the ratio of the speeds at aphelion to perihelion? A. 1/4 B. 1/2 C. 2 D. 4 Now the Earth's North Pole points close to the star Polaris. However, the Earth is wobbling about its polar axis like a top. About how long will it take for the Earth's polar axis to wobble away from and back again to Polaris? A. 200 years B. 2,000 years C. 20,000 years D. 200,000 years "Diurnal Motion " refers to A. the seasonal variation of the Sun's North-South position on the horizon. B. the rising and setting ofthe stars at night as observed on Earth. C. the path a planet moves among the stars. D. the orbial motion ofthe Moon about the Earth. xii i: .-,y .J" The Sun is located at one focus ofthe orbit ofa planet. What is located at the other focus? A. nothing B. the Earth C. the planet itself D. one ofthe other planets Which is true about the constellations? A. Their stars are physically associated with each other. B. The Sun sets in the same constellation each month. C. Both A and B D. They are random projections of stars on the celestial sphere that merely appear to be physically associated. Page 3 22. The Sun's path on the celestial sphere is the A. zenith. B. equator. C. meridian. D. ecliptic. 23. Suppose an artificial satellite is in a circular orbit about the Earth. What can be said about the acceleration of the s atellite? A. Its acceleration is zero. B. It is accelerating because its speed changes constantly. C. It is acCelerating because its direction changes constantly. D. We can tell ifit is accelerating only ifwe can measure the force on it. 24. The Vernal Equinoxis A. the first day of Spring. B. one ofthe two points of intersection of the celestial equator with the ecliptic. C. the reference point of the celestial coordinate system D. all ofthe above 25. The reason Copernicus subscribed to the heliocentric hypothesis was that A. the observations ofVenusian phases convinced him. B. he knew that the planets were in elliptical orbits. C. it was philosophically pleasing to him D. there was official pressure to espouse a heliocentric theory. 26. Aristarchus's estimated distance to the Sun was too small because A. he made, suprisingly, a simple error in trigonometry. B. be used Ptolemy's incorrect "geocentric" model for his calculations. C. he made the measurement during the summer when the Earth is much closer to the Sun. D. his measurement ofthe angle between the Sun and Moon at the moment ofquarter Moon phase was inaccurate. 27. In Irvine, at which ofthe following times is the azimuth of the rising Sun the greatest? :3 I7: i,“ a” A. the winter solstice B. the summer solstice C. the spring equinox D. the autumnal equinox 28. Relative to the stars, the Moon A. remains stationary. B. moves eastward, then westward during a month. C. moves westward. D. moves eastward. Page 4 29. Ifthe rmsses of the Sun and Birth each were doubled, the force of gravity between them would A. remain the same. B. double. C. go up by 4times. D. go up by 16 times. 30. What would happen ifthe Moon moved westward rather than eastward among the stars? A. there would be no noticeable effects B. the sidereal month would be the same as the synodic month C. the siderealmonth would be longer than the synodic month D. the sidereal month would be shorter than the synodic month 31. In the horizon coordinate systemthe point on the sky directly overhead is called the A. azimuth. B. zenith. C. meridian. D. altitude. 32. In the heliocentric model of the solar system, retrograde motion occurs when two planets are farthest apart. two planets are on opposite sides ofthe Sun. two planets pass each other in their orbits. one ofthe planets is nearest the Sun in its orbit. POP”? 33. A superior planet is found to have a synodic period of9/8 years. How many years does it take this planet to complete one orbit around the Sun in the Heliocentric model of Copernicus? A. 8 B. 9 C. 17/9 D. Trick question. All planets orbit the sun in the same amount oftime. 34. Which ofthe following was NOT an influential contribution to astronomy made by Tycho Brahe? A. the rejection of the Heliocentric model. *"P B. made a wealth ofobservations that were much more precise than previous observations. C. bequeathed his astronomicaldata to Kepler D. made the first discovery ofstellar parallax 35. Assume that Saturn is 10 times as far fromthe Sun as the Earth, and that it has lOOtimes the mass ofthe Earth. 7 The gravitational force between Saturn and the Sun is A. 100 times the force between the Earth and Sun. B. 10 times the force between the Earth and Sun. C. equal to the force between the Earth and Sun. D. one-tenth the force between the Earth and Sun. E. 11'100 the force between the Earth and Sun. Page 5 ...
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This test prep was uploaded on 02/19/2008 for the course PHYS 20A taught by Professor Staff during the Spring '02 term at UC Irvine.

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Physics20A S02 MIDTERM EXAM - Version D - VERSION: D...

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