A : The direction of velocity of an object can be reversed with constant acceleration.
R : A ball projected upward reverse its direction under the effect of gravity.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statement, then mark (4).

Answer

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

**Assertion (A)**: The direction of velocity of an object can be reversed with constant acceleration.
**Reason (R)**: A ball projected upward reverses its direction under the effect of gravity.

### Step 1: Analyze the Assertion
- The assertion states that the direction of velocity can be reversed with constant acceleration. This is true. For example, if an object is moving in one direction and a constant acceleration acts in the opposite direction, the object will eventually stop and then start moving in the opposite direction.

**Hint**: Think about how forces can change the motion of an object.

### Step 2: Analyze the Reason
- The reason states that a ball projected upward reverses its direction under the effect of gravity. This is also true. When a ball is thrown upwards, it moves against the gravitational force, which acts downward. As it rises, its upward velocity decreases until it reaches a maximum height (where its velocity is zero), and then it starts to fall back down, reversing its direction.

**Hint**: Consider how gravity affects the motion of objects thrown upwards.

### Step 3: Determine the Relationship Between Assertion and Reason
- While both the assertion and reason are true, the reason provided (the ball's motion) does not serve as a direct explanation for the assertion. The assertion is a general statement about any object under constant acceleration, while the reason is a specific example of this phenomenon.

**Hint**: Reflect on whether the reason directly explains the assertion or if it's just an example.

### Step 4: Conclusion
- Since both the assertion and reason are true, but the reason does not explain the assertion, the correct option is:
**Option 2**: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

**Final Answer**: Option 2.