AP Physics 1 Question 223: Answer and Explanation

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Question: 223

4. A ball of mass m traveling horizontally with velocity v strikes a massive vertical wall and rebounds back along its original direction with no change in speed. What is the magnitude of the impulse delivered by the wall to the ball?

  • A. mv
  • B. mv
  • C. 2mv
  • D. 4mv

Correct Answer: C



The impulse delivered to the ball is equal to its change in momentum. The momentum of the ball was mv before hitting the wall and m(-v) after. Therefore, the change in momentum is m(-v) - mv = -2mv, so the magnitude of the momentum change (and the impulse) is 2mv.