The Early Bird communication satellite hovers over the same point on Earth's equator indefinitely, because
A) other forces than Earth's gravity act on it.
B) it pulls as hard on Earth as Earth pulls on it.
C) it is beyond the main pull of Earth gravity.
D) it is kept aloft by ground control.
E) its orbital period is 24 hours.
Answer: E
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A. I and II B. I and III C. II and III D. III and IV E. II and IV
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A. The period does not change. B. The period increases. C. The period decreases. D. The period becomes zero. E. The period increases if the upward acceleration is more than g/2 but decreases if the upward acceleration is less than g/2.
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Indicate whether the statement is true or false
The direction of the electric field halfway between an electron and a proton is
A) undefined since the electric field is zero. B) directed toward the proton. C) directed toward the electron. D) perpendicular to the line from the electron to the proton. E) cannot be determined.