Velocity Addition: A star is moving toward Earth at 90% the speed of light. The star emits light, which moves away from the star at the speed of light. What do Earth-based astronomers measure for the speed of this light?
A. c
B. 1.9c
C. 1.2c
D. 0.98c
E. 0.95c
Answer: A
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Atmosphere pressure on mars is roughly half that of Earth's at sea level
Indicate whether the statement is true or false.
If a sphere of material with average density 1000 kg/m3 were made large enough to reach the Schwarzschild radius, what would be its mass?
A) 4.3 x 108 m B) 4.0 x 1011m C) 1.3 x 1028 kg D) 2.7 x 1038 kg E) 3.4 x 1045 kg
The very earliest Greek theory of the structure of the universe pictured Earth at the center with the planets revolving around it at an unchanging rate in simple circles. The Greeks later revised this theory because
A) they didn't believe the theory was sufficiently beautiful to represent the eternal gods. B) they observed that the planetary motions are irregular and include such things as retrograde motion. C) certain observations led them to the conclusion that Earth has a spherical shape. D) they came to believe that the sun should be at the center of things. E) Actually, the Greeks never did abandon this theory--the theory was not altered until the time of Copernicus.
A loop of wire is oriented in the magnetic field as shown (the plane of the loop is perpendicular to the direction of the magnetic field and the magnetic field strength increases with height). Which of the following is true? 
A. There will be an induced current only if the loop is moved to the right B. There will be an induced current only if the loop is moved to the left C. There will be an induced current only if the loop is moved upward D. There will be an induced current if the loop is moved either up or down E. There will be an induced current only if the loop is moved downward