(A):A negative acceleration of a body is associated with a slowing down of a body.
(R ):Acceleration is vector quantity.

Answer

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

### Step 1: Analyze the Assertion (A)
The assertion states: "A negative acceleration of a body is associated with a slowing down of a body."

- **Understanding Negative Acceleration**:
- Negative acceleration (also known as deceleration or retardation) occurs when the velocity of an object decreases over time.
- For example, if a car is moving forward and begins to slow down, it experiences negative acceleration.

- **Conclusion for Assertion**:
- The assertion is true because negative acceleration indeed corresponds to a decrease in the speed of the body.

### Step 2: Analyze the Reason (R)
The reason states: "Acceleration is a vector quantity."

- **Understanding Acceleration as a Vector**:
- Acceleration is defined as the rate of change of velocity with respect to time and has both magnitude and direction.
- The direction of acceleration can be in the same direction as the velocity (speeding up) or in the opposite direction (slowing down).

- **Conclusion for Reason**:
- The reason is also true because acceleration is indeed a vector quantity.

### Step 3: Determine the Relationship Between A and R
- The assertion (A) is true, and the reason (R) is true.
- However, the reason does not explain the assertion. The fact that acceleration is a vector does not inherently explain why negative acceleration leads to slowing down.

### Final Conclusion
- Both the assertion and the reason are correct, but the reason is not the explanation for the assertion.

### Summary
- **Assertion (A)**: True
- **Reason (R)**: True
- **Correct Answer**: Both A and R are correct, but R is not the explanation for A.

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