Centripetal Force: At what RPM must you gainer at to decapitate yourself?

Click For Summary
SUMMARY

The discussion centers on calculating the rotational speed required for decapitation during a gainer maneuver, with the necessary force estimated between 5000 and 6000 N. Using the formula Fc = mω²r, participants analyze the implications of body weight (75 kg) and head mass (5 kg) to determine the critical angular velocity (ω) for potential injury. Additionally, the feasibility of Guile's Flash Kick from Street Fighter 2 is examined, considering the speed of sound for the kick's execution and its impact force.

PREREQUISITES
  • Understanding of centripetal force and its formula (Fc = mω²r)
  • Basic knowledge of physics, specifically rotational dynamics
  • Familiarity with the concept of force and mass in injury mechanics
  • Awareness of biomechanics related to acrobatic movements
NEXT STEPS
  • Calculate the angular velocity (ω) for various body weights and head masses
  • Research injury thresholds related to rotational forces in gymnastics
  • Explore the physics of acrobatic maneuvers and their safety implications
  • Investigate the biomechanics of high-speed impacts in martial arts
USEFUL FOR

Acrobats, martial artists, sports scientists, and anyone interested in the physics of high-risk movements and injury prevention.

groinsmash
Messages
2
Reaction score
0
Ok, here's a question I've been worrying about recently:

If you were to be rotated about your waist, at what rotational rate would your body begin to tear apart, specifically decapitation?

Basically, I've been doing lots of gainers (running back-flips) and I'm concerned that if I get really good at them I might accidentally decapitate myself.

Assume the force required to achieve decapitation is between 5000 and 6000 N (refer to http://en.wikipedia.org/wiki/Hanging#Long_drop for information about this number).

Here's some other information (you may or may not need it...).

Height: 180cm​
Weight: 75kg​

Also, assume the gainer is perfectly laid out and not in tuck or pike position.

As a corollary to this question, find out if Guile's Flash Kick in Street Fighter 2 is feasible without decapitation (assume tips of feet are traveling at the speed of sound). If it is not feasible, find out the tangential velocity Guile's head would be delivered to the enemy and also the force imparted on the enemy (assume Guile's head weighs 4kg and the collision is completely inelastic).
 
Physics news on Phys.org
groinsmash said:
Ok, here's a question I've been worrying about recently:

If you were to be rotated about your waist, at what rotational rate would your body begin to tear apart, specifically decapitation?

Basically, I've been doing lots of gainers (running back-flips) and I'm concerned that if I get really good at them I might accidentally decapitate myself.
Just plug in the numbers and see:

Fc = mω²r

Solve for ω. The mass of your head is probably about 5 kg.