Question

Astronomers making careful observations of the moon’s orbit discover that the orbit is not perfectly circular, nor is it elliptical. which of the following statements supports this observation?

a. The moon and the planet exert forces of equal magnitude on each other

b. There is another celestial body that exerts a gravitational force on the moon

c. The value of the gravitational constant G is different in the location near the planet moon system

d. There is a centripetal force that causes the net force exerted on the moon to be different from the gravitational force

Answer 1

The moon's orbit is not perfectly circular or elliptical because there is a centripetal force that causes the net force exerted on the moon to be different from the gravitational force.

Step-by-step explanation:

The observation that the moon's orbit is not perfectly circular or elliptical can be supported by statement (d): There is a centripetal force that causes the net force exerted on the moon to be different from the gravitational force. When an object moves in a circular path, a centripetal force is required to keep it in that path. In the case of the moon, the gravitational force from the Earth provides the necessary centripetal force to keep it in orbit. Because the moon's orbit is not perfectly circular, there must be a difference between the net force and the gravitational force, which supports the observation.

Answer 2

The Moon's orbit is affected by additional celestial bodies' gravitational forces. This, along with Earth's gravity and the mutual forces of interaction following Newton's third law, results in the observed non-perfectly elliptical orbit. So the correct option is b.

Step-by-step explanation:

If astronomers observe that the Moon's orbit is not perfectly circular nor perfectly elliptical, the observation can be supported by the understanding that there is another celestial body that exerts a gravitational force on the Moon. This celestial body, besides Earth, would influence the Moon's orbit, causing deviations from a simple elliptical path. The correct choice from the provided options is:

• (b) There is another celestial body that exerts a gravitational force on the Moon.

The Moon's orbit is influenced by both the Earth and other celestial bodies, such as the Sun, resulting in a slightly complicated path. This aligns with option (d) from the GRASP CHECK stating that the Moon is affected by the gravitational fields of both the Earth and the Sun, which can sometimes be additive and sometimes opposite, influencing the Moon's trajectory. Newton's third law explains that when Earth exerts a gravitational force on the Moon, the Moon exerts an equal and opposite force on Earth, contributing to the motion of the Earth-Moon system around their common center of mass.