Assertion `:-` A particle has positive acceleration it means that its speed always increases.
Reason `:-`Acceleration is the rate of change of speed with respect to time.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertiion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are False

Answer

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

### Step 1: Understand the Assertion
The assertion states: "A particle has positive acceleration; it means that its speed always increases."

- **Analysis**: Positive acceleration indicates that the velocity of the particle is increasing. However, speed is the magnitude of velocity. If a particle is moving in the negative direction (for example, -4 m/s) and then accelerates positively (to 2 m/s), its speed (which is a scalar quantity) does not always increase; it can decrease in this case. Therefore, the assertion is **false**.

### Step 2: Understand the Reason
The reason states: "Acceleration is the rate of change of speed with respect to time."

- **Analysis**: This statement is incorrect because acceleration is defined as the rate of change of **velocity** with respect to time, not speed. Speed is a scalar quantity, while velocity is a vector quantity that includes direction. Therefore, the reason is also **false**.

### Step 3: Conclusion
Since both the assertion and the reason are false, we conclude that the correct answer is that both the assertion and reason are false.

### Final Answer
Both assertion and reason are false.

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