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
You might also like to view...
Simple Pendulum: A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves upward with constant velocity?
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.
Equation of Traveling Waves: Four waves are described by the following equations, where distances are measured in meters and times in seconds.I. y = 0.12 cos(3x - 21t)II. y = 0.15 sin(6x + 42t)III. y = 0.13 cos(6x + 21t)IV. y = -0.23 sin(3x - 42t)Which of these waves have the same speed?
A. I and II B. I and III C. II and III D. III and IV E. II and IV
The Schwarzschild radius of a black hole is about 3 km per solar mass
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.