Assertion (A): The acceleration of a body moving with constant velocity is zero.
Reason ( R): Acceleration is the rate of change in velocity.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true, but is not the correct explanation of A.
C. A is true but R is false.
D. Both A and R are false.

Explanation

To solve the given question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step 1: Understand the Assertion (A)
Assertion (A) states that "The acceleration of a body moving with constant velocity is zero."

- **Explanation**: When a body is moving with constant velocity, it means that its speed and direction are not changing. Since acceleration is defined as the change in velocity over time, if there is no change in velocity, the acceleration must be zero.

### Step 2: Understand the Reason (R)
Reason (R) states that "Acceleration is the rate of change in velocity."

- **Explanation**: This statement is true. Acceleration is mathematically defined as the change in velocity (Δv) divided by the change in time (Δt). If there is no change in velocity, then the acceleration is zero.

### Step 3: Analyze the Relationship between A and R
Now we need to determine if R is a correct explanation of A.

- Since A states that acceleration is zero when velocity is constant, and R correctly defines acceleration as the rate of change in velocity, we can conclude that R explains why A is true.

### Conclusion
Both the assertion (A) and the reason (R) are true, and R is the correct explanation of A.

### Final Answer
Both A and R are true, and R is the correct explanation of A.

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