The main problem with early attempts to listen for radio signals from space was
A) that they were conducted at relatively low frequencies which have problems penetrating the Earth's upper atmosphere
B) building receivers sensitive enough to detect extraterrestrial signals
C) that they were conducted at relatively high frequencies which have problems penetrating the Earth's lower atmosphere
D) interference by radio waves from the Sun
A
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The energy a white dwarf emits into space is
a. replaced by fusion of hydrogen atoms into helium. b. replaced by fusion of helium atoms into carbon. c. not replaced.
As a rotating gas cloud contracts, it spins:
A) faster due to an increase in angular momentum. B) slower due to a decrease in angular momentum. C) at a constant rate. D) faster due to conservation of angular momentum. E) slower due to conservation of angular momentum.
A planet orbiting the Sun has speed v = ?(GM/d). Escape speed from the Sun is v = ?v(2GM/d), where G is the gravitational constant, M is Sun's mass, and d is the distance from the Sun
Noting that this tells us that escape speed is ?2 times orbital speed, which planet would fly out of the solar system by a 1.5 increase in orbital speed? A) Mercury. B) Venus. C) Earth. D) all of the above E) none of the above
An ice skater glides across a frozen pond at a constant velocity. What is the net force acting on the skater?
A. more than her weight B. equal to her weight C. less than her weight but more than zero D. depends on her speed E. zero