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A professional boxer hits his opponent with a 1000-N horizontal blow that lasts for 0.150 s. (a) Calculate the impulse imparted by this blow. (b) What is the opponent’s final velocity, if his mass is 105 kg and he is motionless in midair when struck near his center of mass? (c) Calculate the recoil velocity of the opponent’s 10.0-kg head if hit in this manner, assuming the head does not initially transfer significant momentum to the boxer’s body. (d) Discuss the implications of your answers for parts (b) and (c).
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Final Answer
  1. $150\textrm{ kg}\cdot\textrm{m/s}$
  2. $1.43 \textrm{ m/s}$
  3. $15.0\textrm{ m/s}$
  4. The velocity when impacting only the head is significant and would result in concussion injury when imparted in such a short time. To achieve a knockout, boxers should strategically aim for the head.
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OpenStax College Physics Solution, Chapter 8, Problem 10 (Problems & Exercises) (2:51)

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