Communications and weather satellites always appear at the same place in the sky, because these satellites are
A) beyond the pull of Earth's gravitational field.
B) moving at a speed just short of escape velocity.
C) orbiting Earth with a 24-hour period.
D) stationary in space.
E) none of the above
Answer: C
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Answer the following statement(s) true (T) or false (F)
1. Fusion power is completely safe and has no radioactive waste disposal problem. 2. The fusion reactions used in thermonuclear bombs and fusion power experiments are exactly the same as those used in the sun.
Both line emission and line ______________ spectra are characteristic for a specific element
Fill in the blank(s) with correct word
You hold a tennis racket in your hand. On top of the racket you have balanced a ball. Which statement is true?
a. The force of your hand on the racket and the force of the ball on the racket are equal and opposite. b. The force of the racket on your hand and the force of the ball on the racket are equal and opposite. c. The force of your hand on the racket and the force of the racket on the ball are equal and opposite. d. The force of the racket on your hand and the force of the racket on the ball are equal and opposite. e. The force of your hand on the racket and the force of the racket on your hand are equal and opposite.
What makes the surface of Io appear red and orange?
A) sulfur expelled by volcanic eruptions B) Rocks on the surface were rusted by oxygen. C) clays on the surface formed in past lakes D) reflection of Jupiter's light off of sheets of ice E) Io's thermal spectrum peaks in the red-orange part of the spectrum.