The Moon s angular diameter in our sky is measured to be 0.5 . From this, we can find
A) the mass density of the Moon if we know its distance from the Earth.
B) diameter of the Moon if we know the Moon s distance.
C) diameter of the Moon with no other information about the Moon.
D) distance to the Moon with no other information about the Moon.

Question

Quizplus · Accepted Answer

We can use the formula for angular diameter to find the actual diameter of the Moon if we know its distance d:

angular diameter = 2 arctan (diameter / 2d)

Since we know the angular diameter (0.5 degrees), we can solve for the diameter of the Moon if we assume a certain distance. Therefore, the answer is B: diameter of the Moon if we know the Moon's distance. If we know the Moon's angular diameter and distance, we can use basic geometry (using tangent function) to find the Moon's diameter. However, knowing the Moon's angular diameter alone does not provide enough information to determine its mass density or distance to Earth.

The Moon S Angular Diameter in Our Sky Is Measured