1 A) gravity. B) the "action-reaction" law C) The tendency of a person to stay in bed in the morning. D) inertia. 2 A) It must be an artificial satellite. B) There must be a force acting on it C) It is not subject to any outside forces. D) None of the above 3 A) A only. B) All but A. C) C only. D) Both C and D. 4 A) F = GMm/r B) F = GMm/r2 C) F = GMm/r3 D) F = Gm2M/r2 5 A) increased by a factor of 3. B) increased by a factor of 9. C) decreased by a factor of 3 D) decreased by a factor of 9. 6 A) increased by a factor of 2. B) increased by a factor of 4. C) decreased by a factor of 2. D) decreased by a factor of 4. 7 A) greater than B) less than C) equal to D) unrelated to 8 A) A body continues in a state of rest or uniform motion in a straight line unless made to change that state by forces acting on it. B) Force equals mass times acceleration, F=ma. C) Every mass exerts a force on any other mass that is proportional to the product of the masses divided by the square of the distance between them. D) When two bodies interact, they create equal and opposite forces on each other. 9 A) A body continues in a state of rest or uniform motion in a straight line unless made to change that state by forces acting on it. B) Every mass exerts a force on any other mass that is proportional to the product of the masses divided by the square of the distance between them. C) Force equals mass times acceleration, F=ma. D) When two bodies interact, they create equal and opposite forces on each other. 10 A) When two bodies interact, they create equal and opposite forces on each other. B) Force equals mass times acceleration, F=ma. C) Every mass exerts a force on any other mass that is proportional to the product of the masses divided by the square of the distance between them. D) A body continues in a state of rest or uniform motion in a straight line unless made to change that state by forces acting on it. 11 A) The tendency of a planet's surface to collapse under gravity. B) How fast an object needs to go to escape a planet's gravity. C) The attraction between the surfaces of two massive objects. D) The gravitational attraction at a planet's or star's surface. 12 A) There is no difference, they are the same. B) Weight is a measure of how much gravity pulls an object; mass is how much matter the object has. C) Mass is the amount of matter an object contains; weight is how much matter an object contains. D) Weight is the amount of matter an object contains; mass is the type of matter an object is made of 13 A) 0 kilograms, because the Moon has no gravity. B) 60 kilograms, because mass does not depend on gravity. C) 120 kilograms, because the Moon's gravity is greater than Earth's. D) 360 kilograms, because the Moon is a spherical object. 14 A) 1.67 pounds. Surface gravity on the Moon is 1/6 that on the Earth. B) 10 pounds. Gravity is the same on the Earth and the Moon. C) 30 pounds. Surface gravity on the Earth is 3 times that on the Moon. D) 60 pounds. Surface gravity on the Earth is 6 times that on the Moon. 15 A) The gravitational attraction at a planet's surface. B) How fast an object needs to go to escape a planet's gravity. C) How far away an object needs to be to escape a planet's gravity. D) How fast an object needs to go to escape hostile space aliens.
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