A : During collision between two objects, the momentum of colliding objects is conserved only in direction perpendicular to line of impact.
R : The force on colliding objects in direction perpendicular to line of impact is zero.

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 falsė statements, then mark (4).

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided:

**Assertion (A):** During collision between two objects, the momentum of colliding objects is conserved only in the direction perpendicular to the line of impact.

**Reason (R):** The force on colliding objects in the direction perpendicular to the line of impact is zero.

### Step-by-Step Solution:

1. **Understanding the Assertion (A):**
- Momentum conservation in collisions occurs when no external forces act on the system.
- In the direction of the line of impact (the direction along which the two objects collide), the forces exerted by the colliding objects on each other are equal and opposite (Newton's Third Law).
- Therefore, the net force in this direction is zero, which implies that momentum is conserved along the line of impact, not just perpendicular to it.

2. **Evaluating the Reason (R):**
- The reason states that the force on colliding objects in the direction perpendicular to the line of impact is zero.
- This is incorrect because while the forces along the line of impact may cancel out, there can still be forces acting in the perpendicular direction (e.g., due to gravity or other external influences).
- Thus, the force in the perpendicular direction is not necessarily zero.

3. **Conclusion:**
- Since both the assertion and the reason are incorrect, we conclude that the correct answer is that both A and R are false.

### Final Answer:
Both the assertion (A) and the reason (R) are incorrect.

---