태권도 물리: Lesson 1 – energy and force

First, we start with E=\frac{1}{2}mv^2+mg_y

  • Let m = mass of the fist and arm of a 45 kg (100 pounds) martial artist, approximately 10 kg (22 pounds).
  • Let v = velocity of the fist in the horizontal, or x direction only. Assume 5 m/s, for discussion sake (to be refined in a later blog).

Second, plug and chug: E_{arm}=\frac{1}{2}(10)(5)^2-(5)(9.8)=125J-49J=76J

Next, let us find the actual force: F_{arm}=(10)(9.8)=980N

This is about 220 pounds of force, if the entire arm is treated as a solid body. This means that a well-trained martial artists can translate 2.2X of his/her mass into a punch! Later we will try to verify that 5 m/s is a good assumption on velocity.

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6 thoughts on “태권도 물리: Lesson 1 – energy and force

  1. Pingback: Week 36 of 213: I want to know God’s thoughts. The rest are only details. « Aerospace Cubicle Engineer (ACE)

  2. Pingback: 태권도 물리: Lesson 4 – Size? Weight? Power? | Aerospace Cubicle Engineer (ACE)

  3. Pingback: 태권도 물리: Lesson 2 – velocity and force | Aerospace Cubicle Engineer (ACE)

  4. Pingback: 태권도 물리: Lesson 3 – energy and force, part 2 | Aerospace Cubicle Engineer (ACE)

  5. Pingback: 태권도 물리: Lesson 3 – energy and force, part 2b | Aerospace Cubicle Engineer (ACE)

  6. Pingback: 태권도 물리: Lesson 5 – Jerk! | Aerospace Cubicle Engineer (ACE)

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