Assertion:The work done by a conservative force such as gravity depends on the initial and final positions only
Reason: The work done by a force can not be calculated if the exact nature of the force is not known.

Options

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

Explanation

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

### Step 1: Analyze the Assertion
The assertion states that "The work done by a conservative force such as gravity depends on the initial and final positions only."

- **Explanation**:
- A conservative force is one where the work done is independent of the path taken and only depends on the initial and final positions.
- For example, when an object is lifted to a height \( h \) against gravity, the work done is given by \( W = mgh \), where \( m \) is the mass of the object and \( g \) is the acceleration due to gravity.
- This work done only depends on the height difference (initial and final positions) and not on the path taken to reach that height.

- **Conclusion**: The assertion is **True**.

### Step 2: Analyze the Reason
The reason states that "The work done by a force cannot be calculated if the exact nature of the force is not known."

- **Explanation**:
- This statement is misleading. While knowing the exact nature of the force can help in calculating work done more accurately, it is not entirely true that work cannot be calculated at all.
- For example, if we know the type of force (like spring force, gravitational force, etc.), we can still use the general formulas to calculate work done.
- Even if the exact nature of the force is not known, we can sometimes make approximations or use average values to estimate work done.

- **Conclusion**: The reason is **False**.

### Final Conclusion
- Since the assertion is true and the reason is false, the correct answer is that the assertion is true but the reason is false.

### Summary of the Solution
- **Assertion**: True
- **Reason**: False
- **Final Answer**: Assertion is true, Reason is false.

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