1. Imagine that the Earth¡¦s spin were to be reversed, so that the planet rotated about its axis from East to West, at the same rate at which it now rotates from West to East. If Earth¡¦s orbital motion about the Sun were unchanged, which of these describe the changes we would observe?
A. The duration of the sidereal day would not change
B. The sidereal day would be 8 minutes longer than it is now
C. The duration of the Solar day would not change
D. The Sun would appear to move along the celestial sphere from East to West once a year
E. The Solar day would be 8 minutes longer than it is now
F. The Sun would appear to move along the celestial sphere from West to East once a year
G. The Solar day would be 8 minutes shorter than it is now
2. Imagine that Earth¡¦s orbital motion about the Sun were in a plane perpendicular to its axis (no tilt). If Earth¡¦s spin were unchanged, which of these describes the changes we would observe?
A. The apparent rotation of the celestial sphere would be precisely unchanged
B. The Sun would appear to move about the celestial equator to the West once a year
C. The seasonal changes in climate and the variations in the amount of daylight would disappear
D. The Sun would appear to move about the celestial equator to the East once a year
E. The apparent rotation of the celestial sphere would be reversed
F. The seasonal changes in the visibility of stars would be largely unchanged
G. The seasonal changes in climate and variations in the amount of daylight would become more dramatic
3. The satellite orbits, as we shall see next week, in a circle in the plane of the Earth¡¦s equator, centered on the Earth¡¦s center, with a radius of approximately 5.6 times the Earth¡¦s radius. This means we cannot assume with high precision that it appears in the same apparent position in the sky from all points on Earth. For example, while the celestial equator appears to coincide with the horizon as viewed from either pole, the satellite will appear below the horizon. Use the small angle approximation to estimate the latitude at which the satellite will appear to lie on the horizon.
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