CT9-1CT9-1At a particular instant, two asteroids in inter-galactic space are a distance r = 20 km apart. Asteroid 2 has 10 times the mass of asteroid 1. The magnitudes of the accelerations of asteroids 1 and 2 are a1 and a2, respectively. What is the ratio 21aa ?A: 10B: 1/10C: 1D: cannot be determined.rmm = 10 m11221CT9-2A satellite is in circular orbit at an altitude of 100 miles above the surface of the Earth.The satellite’s pre-launch weight is its weight measured on the ground. The magnitude of the force of gravity on the satellite while it is in orbit is..A: slightly greater than its pre-launch weight.B: the same as its pre-launch weight.C: slightly less than its pre-launch weight.D: much less than its pre-launch weight, but not zero.E: zero. EarthCT9-3Planet X has the same mass as the Earth, but 1/2 the radius. (Planet X is more dense than Earth). What is the acceleration of gravity on Planet X?A: g (same as Earth) B: 2gC: 4g D: 8g E: None of these.CT9-4.A rock is released from rest at a point in space far from Earth, beyond the orbit of the Moon. The rock falls toward the Earth and crosses the orbit of the Moon. When the rock is the same distancefrom the Earth as the Moon, the acceleration of the rock is .. (Ignore the gravitational force between the rock and the Moon.)A: greater B: smaller C: the same as the acceleration of the Moon.As the rock falls toward the Earth, its acceleration is..A: constant. B: not constant.EarthMoonrockCT9-5. At time t=0, a satellite in circular orbit about the Earth is directly over Denver, 300 miles above the city, and traveling eastward at 16,000 mph. At the same time, a rock is released from rest 300 miles above the city, very near the satellite. True or False: at t=0+, the accelerations of the rock and the satellite are identical in magnitude and direction.A: True B: FalseDenver rock satelliteCT9-6. Two satellites, A and B, are in circular orbit around the earth. The distance of satellite B from the center of the Earth is twice that of satellite A. What is the ratio of the magnitudes of the accelerationsof A to B?aaAB.... A: 1 B: 2 C: 4D: 1/2 E: 1/4A BCT9-7.A planet in elliptical orbit around a star moves from the point in its orbit furthest from the star (A) to the closest point (P). The work done by the force of gravity during this movement is:A: zero B: Positive C: Negative.The planet executes one complete orbit starting from point A and returning to A. The work done by the force of gravity during this orbit is:A: zero B: Positive C: Negative.A PCT9-8Kepler's third law states that the ratio 32rT is a constant for all the planets. The period T of the Earth is 1 year. An astronomical unit (1 A.U.) is defined as the mean distance from the Earth to the Sun, therefore the mean Earth-Sun distance is 1A.U. Consider an asteroid in circular orbit around the Sun with radius r = 2A.U. The period of the asteroid is..A: 2 years. B: 3 years C: 23/2 2.83 years.D: 22/3 1.59 years E: None of these.CT9-9. Does escape velocity depend on launch angle? That is, if a projectile is given an initial speed vo, is it more likely to escape an (airless) planet, if fired straight up than if fired at an angle? A: Yes B: NoCT9-10.A satellite is in circular orbit around a planet that has a very tenuous atmosphere extending up to the altitude of the satellite. Due to atmospheric drag, the speed of the satellite…A: increases B: decreasesC: remains constantCT9-11Suppose the Earth had no atmosphere and a projectile was fired from a mountain top with sufficient speed to put it in circular orbit.The magnitude of the acceleration of the projectile while in orbit would beA: much less than g (because it doesn't fall to the ground)B: much greater than gC: approximately gD: Impossible to tell.CT9-12Suppose a projectile is fired straight upward from the surface of an airless planet of radius R with the escape velocity vesc (meaning theprojectile will just barely escape the planet's gravity -- it will assymtotically approach infinite distance and zero speed.) What is the projectile's speed when it is a distance 4R from the planet's center (3R from the surface).A: 1/2 vescB: 1/4 vescC: 1/9 vescD: 1/3 vescE: None of these is correct.(Ignore the gravity of the Sun and other astronomical bodies.)CT9-13. An object moves along the x-axis . The potential energy U(x) vs. position x is shown below.x U(x) x=A When the object is at postion x=A, which of the following statements must be true.A: The velocity is negative, i.e. along the -x direction.B: The acceleration is negative.C: The total energy is negative.D: The kinetic energy is positive.E: None of these statements is always true.CT9-14.A planet is in elliptical orbit around the Sun. The zero of potential energy U is chosen at r = , so U rGMmr( ) . How does the magnitude of U U U compare to the KE?A: U> KE B: U< KE C: U=KED: depends on the position in the orbit.CT9-14Astronaut Dave Bowman is standing in the centrifuge of the spaceship Discovery. He drops his pen and observes it fall to the floor. Which statement below is most accurate?A: After Bowman releases the pen, the net force on the pen is zero.B: The pen falls because the centrifugal force pulls it toward the floor.C: The pen falls because the artificial gravity pulls it toward the
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