Satellites: the Moons of Mars, Phobos (Fear) and Deimos (Terror)

question 18

Multiple Choice

Satellites: The moons of Mars, Phobos (Fear) and Deimos (Terror) , are very close to the planet compared to Earth's Moon. Their orbital radii are 9,378 km and 23,459 km respectively. What is the ratio of the orbital speed of Phobos to that of Deimos?

• A) 0.2528
• B) 0.3998
• C) 1.582
• D) 2.858
• E) 3.956

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Definitions:

Urban Sprawl

The uncontrolled expansion of urban areas into the surrounding countryside, often leading to environmental and infrastructural issues.

Mortality Rate

A measure of the decrease in population due to deaths; often expressed as the number of deaths per 1,000 people in a particular population.

Fertility Rate

A measure of population growth through reproduction; often expressed as the number of births per 1,000 people in a particular population or the average number of children a woman would bear over a lifetime.

Renewable Resource

A natural resource that can replenish itself over time through natural processes, such as sunlight, wind, rain, tides, and geothermal heat, making it sustainable for ongoing use.