Comparing momentum change on impact: rubber ball vs. lead ball A rubber ball rebounds from a wall, but a lead ball of the same mass and speed strikes the same wall and then falls down without rebounding. Which statement is correct regarding the change in momentum during impact?

Introduction / Context:
Momentum change in collisions depends on whether the object rebounds or stops. The rebound reverses the normal component of velocity, increasing the total change in momentum compared to a case where the body merely comes to rest against the surface.

Given Data / Assumptions:

• Equal masses m and equal incident speeds for both balls.
• Both strike the same rigid wall head-on (consider the normal component).
• Rubber ball rebounds (e > 0), lead ball effectively does not rebound (e ≈ 0).

Concept / Approach:
Change in momentum Δp along the line of impact equals m * (v_after − v_before). If the body stops, v_after ≈ 0 → Δp ≈ −m * v_before (magnitude m * v). If it rebounds with nearly equal speed in the opposite direction, v_after ≈ −v_before → Δp ≈ −2 m * v_before (magnitude 2 m * v), which is larger.

Step-by-Step Solution:

Verification / Alternative check:
Impulse J equals change in momentum. A larger rebound speed implies a larger impulse from the wall, consistent with higher Δp for the rubber ball.

Why Other Options Are Wrong:

• Equal changes: false unless both either stop or rebound identically.
• “Momentum of rubber ball is less than lead ball” before impact: masses and speeds are equal, so initial momenta are equal.
• “Lead ball change greater”: contradicts the stop vs. rebound analysis.

Common Pitfalls:
Comparing momenta instead of changes in momentum; ignoring direction when evaluating Δp vectors.

Final Answer:
Change in momentum suffered by the lead ball is less than that of the rubber ball