The gravity at Earth’s surface

————————————————- Quiz 7 ————————————————- Top of Form Please Note: It is recommended that you save your response as you complete each question. | Question 1| | (1 point)Save| Compared to the gravity at Earth’s surface, Earth’s gravity at a distance twice as far from Earth’s center is | a)| one half as much| | b)| one fourth as much| | c)| one sixteenth as much| | d)| zero| Question 2| | (1 point)Save| The potential energy of a satellite in a circular orbit is | a)| the same everywhere| | b)| greatest at the apogee (farthest point)| | c)| greatest at perigee (nearest point)| d)| the same as its kinetic energy| Question 3| | (1 point)Save| A communications satellite that orbits at a fixed part of the sky | a)| travels at a speed of 8 km/s| | b)| takes 24 hours to complete each orbit| | c)| travels at a speed slightly greater than 8 km/s| | d)| has zero orbital speed and doesn’t move| Question 4| | (1 point)Save| A spacecraft on its way from Earth to the Moon is pulled equally by Earth and Moon when it is | a)| closer to the Earth’s surface| | b)| closer to the Moon’s surface| | c)| halfway from Earth to Moon| | d)| at no point, since Earth always pulls more strongly| Question 5| | (1 point)Save|

When a projectile achieves escape speed from Earth, it | a)| outruns the influence of gravity, but is never beyond it| | b)| forever leaves Earth’s gravitational field| | c)| comes to an eventual stop, eventually returning to Earth at some future time| | d)| likely becomes a black hole| Question 6| | (1 point)Save| A ball rolling along a bowling alley maintains its speed because | a)| it has inertia| | b)| gravity doesn’t pull on it while moving| | c)| there is no horizontal force acting on the ball| | d)| it behaves as a projectile| Question 7| | (1 point)Save| If you drop a ball it will fall 5 m in the first second of fall.

If instead you toss it sideways, in one second it will fall beneath its straight-line path a vertical distance of | a)| less than 5 m| | b)| 5 m| | c)| more than 5 m| | d)| none of these| Question 8| | (1 point)Save| A ball is thrown horizontally from atop of a 5-meter platform and travels a horizontal distance of 15 meters before hitting the ground below.

The initial speed of the ball must have been about | a)| 5 m/s| | b)| 10 m/s| | c)| 10 m/s2| | d)| 15 m/s| Question 9| | (1 point)Save| While a projectile moves horizontally with no change in motion, it moves vertically | a)| also with no change in motion| b)| under the influence of gravity| | c)| equal vertical distances in equal times| | d)| none of these| Question 10| | (1 point)Save| The magnitude of G indicates than gravity is | a)| a relatively weak force| | b)| relatively strong force| | c)| responsible for the orbiting of planets| | d)| responsible for all falling objects| Question 11| | (1 point)Save| The concept of free falling objects applies to | a)| apples| | b)| the Moon| | c)| the planets| | d)| all of these| Question 12| | (1 point)Save| If the Sun were half as massive, its pull on Mars would be | a)| unchanged| | b)| twice| | c)| half| d)| four times as much| Question 13| | (1 point)Save| Present speculation about the universe is that it is | a)| shrinking| | b)| remaining steady| | c)| growing| | d)| accelerating outward| Question 14| | (1 point)Save| Current speculation about the age of the universe is | a)| still not known| | b)| about 7000 years| | c)| some 13. 7 billion years| | d)| infinite| Question 15| | (1 point)Save| If the mass of the Sun and a planet that orbits the sun are both doubled, with the distance being the same, the force of gravity between them | a)| remains unchanged| | b)| doubles| | c)| quadruples| | d)| increases by eight|

Question 16| | (1 point)Save| The Moon falls toward the Earth in the sense that it falls | a)| with an acceleration of 10 m/s2, as do apples on Earth| | b)| beneath the straight-line path it would take if there were no gravity| | c)| both of the above| | d)| none of the above| Question 17| | (1 point)Save| The speed needed for a probe to escape planet Earth is about | a)| 8 km/s| | b)| 9. 8 km/s| | c)| 11. 3 km/s| | d)| 40 km/s| Question 18| | (1 point)Save| When an Earth satellite makes a circular orbit, it has constant | a)| speed| | b)| distance from the Earth| | c)| force of gravity on it| | d)| all of the above|

Question 19| | (1 point)Save| The potential energy of a satellite in an elliptical orbit is | a)| the same everywhere| | b)| greatest at the apogee (farthest point)| | c)| greatest at perigee (nearest point)| | d)| the same as its kinetic energy| Question 20| | (1 point)Save| Consider a space probe whose distance from Earth’s center is four Earth-radii. Compared with the probe’s weight at Earth’s surface, its gravitational attraction to Earth is about | a)| one half as much| | b)| one fourth as much| | c)| one sixteenth as much| | d)| zero| Save All Responses | | Go To Submit Quiz | Bottom of Form