Assertion: In inelastic collision, linear momentum of system does not remain constant during collision. But before collision and after collision, it is constant.
Reason: In elastic collision, momentum remains constant during collision also.

Options

A. If both Assertion 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 both the assertion and the reason provided regarding inelastic and elastic collisions.

### Step 1: Understand the Assertion
The assertion states that in an inelastic collision, the linear momentum of the system does not remain constant during the collision, but it is constant before and after the collision.

**Explanation**:
- Inelastic collisions involve internal forces acting between the colliding bodies. During the collision, these forces can cause changes in momentum, meaning that the momentum of the system may not be constant at every instant during the collision.
- However, the total momentum of the system (the sum of the momenta of all objects involved) is conserved when considering the entire duration of the collision (before and after).

### Step 2: Understand the Reason
The reason states that in an elastic collision, momentum remains constant during the collision as well.

**Explanation**:
- In elastic collisions, both momentum and kinetic energy are conserved. This means that during the collision, the total momentum of the system remains constant throughout the interaction.
- Therefore, the reason provided is correct as it accurately describes the behavior of momentum in elastic collisions.

### Step 3: Conclusion
Both the assertion and the reason are correct statements. However, the reason does not explain the assertion. The assertion is about inelastic collisions, while the reason discusses elastic collisions, making them independent statements.

### Final Answer
The correct conclusion is that both the assertion and the reason are correct, but the reason is not the correct explanation for the assertion. Thus, the answer is option B.

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