Assertion: An object can have constant speed but variable velocity.
Reason: Speed is a scalar but velocity is a vector quantity.

Options

A. If both assertion `&` Reason are True `&` the Reason is a corrrect explanation of the Asserion.
B. If both Assertion `&` Reason are True but Reason is not correct explanation of the Assertion.
C. If Assertion is Trie but the Reason is False.
D. If both Assertion `&` Reason are false

Answer

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

### Step 1: Understand the Assertion
The assertion states that "An object can have constant speed but variable velocity."

- **Constant Speed**: This means that the object is covering equal distances in equal intervals of time.
- **Variable Velocity**: This means that the object's direction of motion is changing, even if the speed remains the same.

### Step 2: Understand the Reason
The reason states that "Speed is a scalar but velocity is a vector quantity."

- **Speed**: A scalar quantity that only has magnitude (how fast an object is moving).
- **Velocity**: A vector quantity that has both magnitude and direction (how fast and in which direction an object is moving).

### Step 3: Analyze the Relationship
Now, we need to see if the assertion is true and if the reason correctly explains it.

1. **Assertion Analysis**:
- An object can move in a circular path at a constant speed (e.g., a car moving around a circular track at a constant speed). Here, the speed remains constant, but the direction changes continuously, leading to a change in velocity.
- Therefore, the assertion is **true**.

2. **Reason Analysis**:
- The reason correctly states that speed is a scalar and velocity is a vector. This distinction is crucial because it explains why an object can have constant speed while its velocity changes due to a change in direction.
- Therefore, the reason is also **true**.

### Step 4: Conclusion
Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that the correct option is:

**Both assertion and reason are true, and the reason is a correct explanation of the assertion.**