Phobos Orbits Mars in a Prograde Orbit with a Period

question 173

Multiple Choice

Phobos orbits Mars in a prograde orbit with a period less than the rotational period of Mars itself.What consequence follows from this?

• A) Phobos rises in the west and sets in the east.
• B) Phobos rises in the east and sets in the west.
• C) Phobos is in a stationary orbit, always over the same point on Mars.
• D) The situation described violates Kepler's third law: The farther out an orbit, the longer its period.

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Definitions:

Judgment Sampling

A nonprobability method of sampling whereby elements are selected for the sample based on the judgment of the person doing the study.

Cluster Sampling

A probability sampling method in which the population is first divided into clusters and then a simple random sample of the clusters is taken.

Simple Random Sampling

A sampling method where each member of the population has an equal chance of being selected, ensuring unbiased representation.

Stratified Simple Random Sampling

A sampling method that divides a population into smaller groups or strata and then selects random samples from each stratum.