Which of the following correctly describe the gravitational attraction between Earth and the Moon?
-The Earth and the Moon exert equal size gravitational forces on each other.
-The gravitational force of the Moon on the Earth is towards the Moon.
-Both the Earth and the Moon exert a gravitational force on each other.
-The gravitational force of the Earth on the Moon is away from the Earth.
The correct answer is: Both the Earth and the Moon exert a gravitational force on each other.
To understand why this is the correct answer, let's go through each statement.
- The Earth and the Moon exert equal-sized gravitational forces on each other: This statement is incorrect. According to Newton's Law of Universal Gravitation, the gravitational force between two objects is proportional to the product of their masses and inversely proportional to the square of the distance between them. Therefore, since the mass of the Earth is much larger than the mass of the Moon, the gravitational force exerted by the Earth on the Moon is much greater than the force exerted by the Moon on the Earth.
- The gravitational force of the Moon on the Earth is towards the Moon: This statement is also incorrect. The direction of the gravitational force is always towards the center of mass of an object. Since the Earth is much more massive than the Moon, the center of mass of the Earth-Moon system is closer to the center of the Earth. Therefore, the gravitational force of the Moon on the Earth is towards the center of mass, not towards the Moon itself.
- Both the Earth and the Moon exert a gravitational force on each other: This statement is correct. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. So when the Earth exerts a gravitational force on the Moon, the Moon also exerts an equal and opposite gravitational force on the Earth. These forces are of the same magnitude but in opposite directions.
- The gravitational force of the Earth on the Moon is away from the Earth: This statement is incorrect. As mentioned earlier, the gravitational force is always towards the center of mass. So, the gravitational force of the Earth on the Moon is towards the center of mass of the Earth-Moon system, not away from the Earth.
In conclusion, the only correct statement among the given options is that both the Earth and the Moon exert a gravitational force on each other.