Assertion: If the head of a right handed screw rotates with the body, the screw advances in the direction of the angular velocty.
Reason: For rotation about a fixed axis, the angular velocity vector lies along the axis of rotation.

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 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-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that if the head of a right-handed screw rotates with the body, the screw advances in the direction of the angular velocity.
- A right-handed screw moves forward when turned clockwise. This is based on the right-hand rule, where if you curl the fingers of your right hand in the direction of rotation (clockwise), your thumb points in the direction of the screw's advancement.

2. **Applying the Right-Hand Rule**:
- When you rotate the screw clockwise, the angular velocity vector points along the axis of rotation (outward from the screw head).
- According to the right-hand rule, the thumb (representing the direction of the angular velocity) indicates the direction in which the screw advances.

3. **Understanding the Reason**:
- The reason states that for rotation about a fixed axis, the angular velocity vector lies along the axis of rotation.
- This is a fundamental property of rotational motion. The angular velocity vector (often denoted as \(\vec{\omega}\)) indeed points along the axis of rotation.

4. **Evaluating the Assertion and Reason**:
- Both the assertion and reason are correct.
- The reason provides a valid explanation for the assertion because it describes the relationship between angular velocity and the direction of motion for a rotating object.

5. **Conclusion**:
- Since both the assertion and reason are true, and the reason correctly explains the assertion, we can conclude that the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
Both assertion and reason are true, and the reason is the correct explanation of the assertion.

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