Final answer:
The student's task is to match scientific notations to the size of various objects. After analysis, an elephant's height would be more reasonably measured in meters, the Earth-Moon distance in the order of 10^8 meters, the width of a grain of salt is appropriately described in micrometers, and the distance of a marathon is accurately given in the question.
Step-by-step explanation:
The student's question involves determining the most reasonable measurement for various objects by matching given scientific notations to the size of the objects. Measurements in physics often use scientific notation to handle large or small numbers efficiently. Let's go through each object to match the best fitting measurement.
- Height of an Elephant: Elephants are large terrestrial animals, and an adult elephant's height can range up to around 4 meters. Thus, the most reasonable measurement would not be 3.8 × 10^5 kilometers, as this is a tremendously exaggerated number for an elephant's height.
- Distance from Earth to the Moon: The average distance to the moon is about 384,400 kilometers, so a measurement such as 9.46 × 10^12 kilometers is far too large to represent this distance.
- Width of a Grain of Salt: A grain of sand, which is larger than a grain of salt, is about 1 millimeter long. The width of a grain of salt would be reasonably measured in micrometers, so 2 × 10^(-2) micrometers may be a reasonable representation for its size.
- Distance of a Marathon: A marathon is a long-distance running race with a length of 42.195 kilometers. Therefore, 4.22 × 10^1 kilometers is a practical measurement and closely matches the actual length of a marathon.
Based on the given information and realistic benchmarks, the correct measurements would likely be as follows:
- Height of an Elephant: A more appropriate scientific notation for an elephant's height could be in meters, not kilometers.
- Distance from Earth to the Moon: A scientific notation of the order of 10^8 meters (or 10^5 kilometers) would be more accurate.
- Width of a Grain of Salt: The given scientific notation in micrometers is actually reasonable.
- Distance of a Marathon: The provided scientific notation is also reasonable for the distance of a marathon.