Astro Ch 4

40) 0 degrees Kelvin is

D) the temperature at which all random particle motion stops.

15) Considering Einstein's famous equation, E = mc^2, which of the following statements is true ?

A) A small amount of mass can be turned into a large amount of energy.

10) The fact that Voyager 10 continues to speed out of the solar system, even though its rockets have no fuel, is an example of

A) Newton's first law of motion.

5) You are standing on a scale in an elevator. Suddenly you notice your weight decreases . What do you conclude?

A) The elevator is accelerating downwards.

33) The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d^2. According to this equation, if the mass of the second object were greater, what happens to the gravitational force between them?

A) The force increases.

21) According to the universal law of gravitation , if you double the masses of both attracting objects, then the gravitational force between them will

A) increase by a factor of 4.

19) According to the universal law of gravitation, the force due to gravity is

A) inversely proportional to the square of the distance between objects.

12) What quantities does angular momentum depend upon?

A) mass, velocity, and radius

34) Newton's version of Kepler's third law states: p^2 = ((4π^2/G (M 1 + M 2)) x a^3 In this equation, what does p represent?

A) the orbital period

8) How does the Space Shuttle take off?

B) Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction.

18) Where does the energy come from that your body uses to keep you alive?

B) It comes from the foods you eat.

9) The speed at which a pool ball moves after being struck by a cue is most directly an example of

B) Newton's second law of motion.

32) The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d^2 . According to this equation, if the distance between two objects increases, what happens to the gravitational force between them?

B) The force decreases.

28) Newton's second law states: sum of forces = mass x acceleration . If a known force was applied to an object with a known mass, how would you predict that object's acceleration?

B) acceleration = sum of forces / mass

7) Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will

B) continue to move in the same way until it is acted upon by a force.

24) The mass of Jupiter can be calculated by

B) measuring the orbital period and distance of one of Jupiter's moons.

35) Newton's version of Kepler's third law states: p^2 = ((4π^2/G (M 1 + M 2)) x a^3 In this equation, what does a represent?

B) the average distance between the two objects

29) The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d^2 . In this equation, what does d represent?

B) the distance between the two objects

14) The amount of gravitational potential energy released as an object falls depends on

B) the distance it falls.

27) Newton's second law states: sum of forces = mass x acceleration . According to this, what property can you determine if you observe the acceleration of an object with a known mass?

B) the sum total of all forces acting on the object

30) The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d^2 . In this equation, what does G represent?

B) the universal gravitational constant

4) If your mass is 60 kg on Earth, what would your mass be on the Moon?

C) 60 kg

6) What would happen if the Space Shuttle were launched with a speed greater than Earth's escape velocity?

C) It would travel away from Earth into the solar system.

39) Newton's version of Kepler's third law states: p^2 = ((4π^2/G (M 1 + M 2)) x a^3 Solve this equation to find the combined mass of a planet and its satellite, given the orbital period and average separation.

C) M 1 + M 2 =(4π 2/G) x (a^3/p^2)

11) Changing the orbit of a spacecraft by firing thrusters is an example of

C) Newton's third law of motion.

13) Gasoline is useful in cars because it has.

C) chemical potential energy.

38) Newton's version of Kepler's third law states: p^2 = ((4π^2/G (M 1 + M 2)) x a^3 According to this, what observational information does one need in order to calculate the combined mass of a planet and its moon?

C) the average distance between the two objects and the orbital period

31) The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d^2 . In this equation, what does M1 represent?

C) the mass of one of the objects

36) Newton's version of Kepler's third law states: p^2 = ((4π^2/G (M 1 + M 2)) x a^3 In this equation, what do M1 and M2 represent?

C) the masses of the two objects

1) What is the acceleration of gravity at the surface of Earth?

D) 9.8 m/s^2 downward

23) According to what we now know from Newton's laws, which of the following best explains why Kepler's second law is true?

D) A planet's total orbital energy must be conserved as it moves around its orbit.

2) If an object's velocity is doubled, its momentum is

D) doubled.

22) The allowed shapes for orbits under the force of gravity are

D) ellipses, parabolas, and hyperbolas.

16) The ultimate source of energy that powers the Sun is

D) mass energy of hydrogen fusing into helium.

37) Newton's version of Kepler's third law states: p^2 = ((4π^2/G (M 1 + M 2)) x a^3 In this equation, what does G represent?

D) the universal gravitational constant

25) The tides on Earth are an example of

D) the universal law of gravitation.

3) As long as an object is not gaining or losing mass, a net force on the object will cause a change in

D) velocity.

17) Which of the following statements correctly describes the law of conservation of energy?

E) The total quantity of energy in the universe never changes.

26) At which lunar phase(s) are tides least pronounced (e.g., the lowest high tides)?

E) both first and third quarters

20) The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them

E) weakens by a factor of 4.

41) Speed and velocity are the same thing.

False

43) If you double the mass of fusion material in a hydrogen bomb, you quadruple the amount of energy generated.

False

44) When energy is converted from one form to another, a tiny amount is inevitably lost.

False

45) Kepler deduced his laws of planetary motion once Newton had published his universal law of gravitation.

False

46) There is no gravity in space.

False

47) Doubling the distance between two objects halves the gravitational force between them.

False

48) The escape velocity from Earth is greater for larger rockets than for small ones.

False

52) When you experience a downward gravitational force from the Earth, the Earth experiences a weaker upward gravitational force from you.

False

53) Planets with larger orbital radii have longer orbital periods only because they have a longer distance to travel in each orbit.

False

42) The Moon is constantly falling toward Earth.

True

49) Tidal friction caused by Earth's stretching from the Moon's gravity is gradually slowing down the rotation of Earth.

True

50) The Moon is slowly moving away from Earth.

True

51) Unbound orbits have more orbital energy than bound orbits.

True

54) Planets with larger orbital radii have longer orbital periods because they both have a longer distance to travel in each orbit and move more slowly.

True

55) To measure the mass of an astronomical object, one can observe the orbital period and distance of a companion.

True