Assertion: The earth is slowing down and as a result the moon is coming nearer to it.
Reason: The angular momentum of the earth-moon system is not conserved.

Options

A. If the both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true and the reason is not the correct explanation of the assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false statements.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "The earth is slowing down and as a result the moon is coming nearer to it." This implies that there is a relationship between the rotational speed of the Earth and the distance of the Moon from the Earth.

### Step 2: Analyze the Reason
The reason given is "The angular momentum of the earth-moon system is not conserved." Angular momentum conservation is a key principle in physics that applies to isolated systems. If the angular momentum of the Earth-Moon system is not conserved, it suggests that there are external torques acting on the system, which could affect the distance of the Moon from the Earth.

### Step 3: Apply Kepler's Laws
According to Kepler's laws of planetary motion, the orbital characteristics of celestial bodies are related to their angular momentum. If the Earth is slowing down (i.e., its rotational speed is decreasing), it can lead to a change in the angular momentum of the Earth-Moon system.

### Step 4: Conclusion on Angular Momentum
If the angular momentum is decreasing, it implies that the Moon is moving closer to the Earth. This is consistent with the assertion that the Moon is coming nearer to the Earth as the Earth slows down.

### Step 5: Evaluate the Relationship
Both the assertion and the reason are true:
- The assertion is true because a slowing Earth can lead to the Moon moving closer.
- The reason is true because the angular momentum of the Earth-Moon system is not conserved due to external factors.

### Final Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, the correct option is that both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

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