Given that there are several hundred billion stars in the Milky Way Galaxy and preliminary data from exoplanet studies suggest that as many as one in five star systems may have one or more habitable planets, then a reasonable estimate for the number
of habitable planets could be about A) 100 billion or more
B) 1 billion or more
C) 100 million or more
D) 10 million or more
A
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Phase Angles: A 200-? resistor, a 40-mH inductor, and a 2.0-?F capacitor are connected in series with a 120-V rms source at 1.0 kHz. What is the phase angle of this circuit?
A. 49° B. 90° C. 41° D. 0° E. 45°
As a body falls through air starting from rest, its acceleration
a. is zero. b. stays constant. c. continuously decreases. d. continuously increases. e. gets smaller and smaller, eventually approaching zero.
A projectile is launched at an angle less than 30° and at speed v. Which will increase the projectile's range more, ignoring atmospheric drag?
a. doubling the launch angle b. increasing the speed of launch by 50% c. reducing the mass of the projectile d. launching on February 29th
Suppose it turns out that one in 1 million stars has a planet that at some point in its history is home to an advanced civilization. Then the total number of civilizations that have arisen in our galaxy would be closest to ________
A) 40,000 B) 400,000 C) 40 D) 4,000 E) 400