Question

1. the same side of the moon always faces earth because the period of revolution of the moon is

(1) shorter than the period of rotation of earth
(2) equal to the period of rotation of earth
(3) equal to the period of rotation of the moon
(4) shorter than the period of rotation of the moon

1. base your answer to the following question on the diagram below and on your knowledge of earth science. the diagram represents earth in its orbit around the sun. locations a through d represent four positions of earth in its orbit. earth is closest to the sun (perihelion) at position a, and farthest from the sun (aphelion) at position c.

how long does it take for earth to go from position a to position d?
(1) 12 months (2) 6 months (3) 9 months (4) 3 months

1. seasonal changes on earth are primarily caused by the

(1) elliptical shape of earths orbit around the sun
(2) parallelism of the suns axis as the sun revolves around earth
(3) changes in distance between earth and the sun
(4) tilt of earths axis as earth revolves around the sun

Explanation:

1. The Moon's revolution period around Earth equals its rotation period (synchronous rotation), so the same side faces Earth.
2. Earth's orbit is divided into 4 positions (A-D), so moving from A to D (1/4 of the orbit) takes ~3 months.
3. Seasonal changes are primarily caused by Earth's axial tilt as it revolves around the Sun.

Answer:

1. (2) equal to the period of rotation of Earth
2. (4) 3 months
3. (4) tilt of Earth's axis as Earth revolves around the Sun