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Mastery Tests

Mastery Test 5

1.   Preview the following selection. Then read it and answer the questions.

Despite the proximity of the Moon to the Earth, the two bodies are glaringly dissimilar. The other three terrestrial planets bear some close similarities to either the Earth or the Moon, but again, each is unique, each teaching us something about the others and about ourselves.

Although Mercury, Venus, and Mars are all close to Earth, they were long shrouded in mystery. Venus is covered with clouds that perpetually hide its surface. Mercury has no significant atmosphere, so its rocky surface is accessible, but it is so close to the Sun that we can observe it effectively only in twilight, when our murky atmosphere provides a poor view. Mars, however, with its surface markings and polar caps, appears intriguingly Earthlike.

Before any physical analysis of the planets is possible, we need distances. The distances in AU between the bodies of the Solar System are found from their orbital locations. The distance in kilometers from the Earth to any of these bodies then gives the number of kilometers per AU (that is, the distance in kilometers between the Earth and Sun) and thus the distances in kilometers between all the planets. In practice, we use Venus, measuring its distance from Earth in kilometers by radar (radio direction and range). (Taken from Astronomy! A Brief Edition, Kaler, James, 10th Ed,. Massachusetts: Addison Wesley, 1997, pgs 192-194)

What is the topic?

 

 
2.   What is the best main idea?  

 
3.   Which paragraph is the central idea found in?  

 
4.   What does glaringly mean in the first sentence?  

 
5.   Which celestial body mentioned has a surface most like Earth?  

 
6.   Preview the following selection. Then read it and answer the questions.

Radar uses artificially produced radio signals sent to and reflected from the body being examined. An astronomical radar system is a radio telescope that can both transmit and receive. A radio signal at a known wavelength is sent toward a target planet. A small portion of the signal bounces off the body and is returned. The time it takes the radio beam to travel to the target and back at the speed of light gives a precise distance. The semimajor axes of the orbits of Mercury, Venus, and Mars, already known in AU, are thereby found to be 57.9, 108, and 228 million km respectively. From the planets’ angular radii and distances we easily calculate respective physical radii of 2,400, 6,100, and 3,400 km. Mercury is 40% larger than the Moon, Venus is nearly a twin of Earth, and the size of Mars falls roughly between that of the Moon and Earth.

Neither Mercury nor Venus has any natural satellites from which to find masses by applying Kepler’s generalized third law. Instead, respective masses of 0.055 and 0.81 that of Earth were originally found from the gravitational perturbations that the two planets exert on each other and on the Earth. The two tiny satellites of Mars allow a determination of 0.11 Earth masses. (Taken from Astronomy! A Brief Edition, Kaler, James, 10th Ed,. Massachusetts: Addison Wesley, 1997, pgs 192-194)

What is the topic?

 

 
7.   What is the main idea?  

 
8.   What is the radius of Mercury?  

 
9.   What is the semimajor axes of the orbit of Mars?  

 
10.   How many sentences are used to explain how radar works?  

 
 


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