71. An asteroid in orbit about the sun has a : 2102147
71. An asteroid in orbit about the sun has a linear speed of 4 km/s when at a distance of closest approach d from the sun. What is its linear speed when it is at its greatest distance from the sun, a distance 2 d?
A. 1 km/s
B. 2 km/s
C. 8 km/s
D. 16 km/s
72. An artificial Earth satellite in an elliptical orbit has its greatest centripetal acceleration when it is at what location?
A. nearest the Earth
B. farthest from the Earth
C. between Earth and Moon
D. between Earth and Sun
73. Which of the following best describes the property of the period of orbital revolution for an Earth satellite?
A. greater when the orbital radius is smaller
B. greater when the orbital radius is larger
C. independent of the orbital radius
D. determined mainly by the satellite's mass
74. Of the nine known planets in our solar system, the innermost is Mercury. When compared to the other planets in the system, Mercury has the:
A. greatest centripetal acceleration.
B. greatest period of revolution.
C. smallest angular velocity.
D. smallest tangential velocity.
75. According to Kepler's second law, Halley's Comet circles the Sun in an elliptical path with the Sun at one focus of the ellipse. What is at the other focus of the ellipse?
B. the Earth
C. The comet itself passes through the other focus.
D. The tail of the comet stays at the other ellipse.