[Friday] How to fry chicken in terms of physics

Even from the school course of physics, we know that energy does not arise by itself and does not disappear into nothing. It cannot be simply created or destroyed, it can only be transformed from one form to another. In this short article, I wanted to clarify what to do in a situation where you have a chicken, no items are available, but you absolutely need to fry this chicken.



On February 14, 2019, the following important question arose in the / r / NoStupidQuestions subreddit: “If kinetic energy is converted into heat, how much do I need to slap the chicken to cook?”

After 3 days, the answer was found and scientifically substantiated.

A bit of physics

So, we will convert the kinetic energy of your kung fu into the thermal energy of a chicken carcass.

For movement with speeds much less than the speed of light (we don’t want to turn the chicken into steam), the kinetic energy of the impact will be image, where m and v are the mass and speed of the arm, respectively. The required amount of heat is calculated by the formula image. In the calculations, we use the following assumptions:

  • The weight of the human palm is on average 0.4 kg.
  • According to the study “THE PHYSICS OF KARATE, 1979” (authors: Michael S. Feld, Ronald E. McNair, Stephen R. Wilk), the average average slap speed was determined experimentally - 11 m / s (25 mph).
  • Let our chicken weigh 1 kg.
  • The specific heat of the bird (laying hens) is 2.72 kJ / kg * ° C.
  • Let's assume that the chicken must reach a temperature of 205 ° C in order to be considered cooked, and also that at the very beginning we have frozen chicken with a temperature of 0 ° C.
  • To simplify the calculations, we will not take into account that the chicken and hand are composed of water, bones, etc. We also assume that the collision is absolutely inelastic, that is, the chicken’s speed is zero after applying kung fu force to it.

After equating the two energies and performing the calculations, we get that one average spank raises the temperature of the chicken by about 0.0089 degrees Celsius. Thus, in order to heat the chicken from 0 to 205 ° C, we need 23,034 strokes.
Well, in order to get a delicious treat in one hit, you need to beat at a speed of 1665.65 m / s (3725.95 mph or 5996.34 km / h).

Probably, in order to carry out such a blow, your hand will have to be dispersed on the North American X-15 suborbital rocket plane. But assuming that you want to safely cook chicken in the indicated way in your kitchen, it would be better to ask Marshal Erickson to slap a billion exploding lights on her face.


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