Assertion In case of projectile motion, the magnitude of rate of change of velocity is variable.
Reason In projectile motion, magnitude of velocity first decreases and then increases during the motion.

Options

A. If both Asseration and Reason are correct and Reason is the correct explanation of Assertion
B. If both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
C. If Assertion is true but Reason is false
D. If Assertion is false but Reason is true

Explanation

To solve the question, we need to analyze the assertion and the reason given regarding projectile motion.

### Step 1: Understand the Assertion
The assertion states that "In case of projectile motion, the magnitude of rate of change of velocity is variable."

**Analysis:**
- The rate of change of velocity is defined as acceleration. In projectile motion, the only acceleration acting on the projectile is due to gravity, which is constant (approximately \(9.8 \, \text{m/s}^2\) downward).
- Therefore, the assertion is incorrect because the magnitude of the rate of change of velocity (acceleration) is constant.

### Step 2: Understand the Reason
The reason states that "In projectile motion, the magnitude of velocity first decreases and then increases during the motion."

**Analysis:**
- When a projectile is launched upwards, its velocity decreases due to the acceleration due to gravity acting in the opposite direction.
- At the peak of its trajectory, the velocity becomes zero momentarily before it starts to descend.
- As it descends, the velocity increases because the direction of the velocity is now the same as the direction of the acceleration (gravity).
- Thus, the reason is correct as it accurately describes the behavior of velocity in projectile motion.

### Step 3: Conclusion
Based on the analysis:
- The assertion is **false** because the rate of change of velocity (acceleration) is constant.
- The reason is **true** because it correctly describes the change in velocity during projectile motion.

Thus, the correct option is that the assertion is false and the reason is true.

### Final Answer:
- Assertion: False
- Reason: True

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