If we have measured a star's apparent brightness and distance, then we can easily calculate its
A) luminosity
B) mass
C) surface temperature
D) radius
E) lifetime
A) luminosity
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Suppose that Earth's spin would suddenly reverse direction, but the direction of Earth's motion around the Sun was preserved. Which of the following changes would you expect to observe?
A. The stars would rise in the west and set in the east. B. The planets would rise in the west and set in the east. C. The Sun would rise in the west and set in the east. D. All of these would be observed. E. None of these choices is correct.
A heavy ball hangs by a string, with a second string attached to its bottom. A slow pull on the bottom string breaks the
A) top string. B) bottom string. C) top or bottom string equally.
A 1200. kg ferryboat is moving south at 20. m/s. Its momentum is
A) 1.7 × 10-3 N?s B) 2.4 × 103 kg?m/s C) 1.2 × 103 kg?m/s D) 24. kN?s E) 6.0 × 102 kg?m/s
An earthquake emits both S-waves and P-waves which travel at different speeds through the Earth. A P-wave travels at 9 000 m/s and an S-wave travels at 5 000 m/s. If P-waves are received at a seismic station 1.00 minute before an S-wave arrives, how far away is the earthquake center?
a. 88.9 km b. 1 200 km c. 675 km d. 240 km e. 480 km