Forces involved in superhuman punches (and the resulting soundwaves)

[PTNLemay]

I was thinking about enhanced soldiers ranging from something like the Master Chief all the way to Superman, and I was wondering... suppose two such super soldiers were fighting one another, at what point would their strikes become harmful to people around them. As in, not just to the combatants but also to normal people sitting around watching the fight.

I've seen the video about the ultimate superman punch (

) but that's a very extreme scenario. I'm thinking more along the lines of... at what point would the shockwave render you deaf, or at what point would the flash of ionizing air blind you. Rather than going all the way and basically vaporizing the surrounding peeps. For the sound I'd need an equation that converts forces (in Joules) to the sound pressure we usually use to measure the force of a sound (in decibels). For the blindness I'll need to determine how much of the energy in a kinetic impactor gets converted into visible light (and when it starts to happen). I found some hints that sound damage can start at around 80 - 120 dB, but that's obviously over long term exposures. These punches would be short quick blasts. Some guns produce 170 dB, and the people using them don't immediately go deaf.

I just think it'd be funny if in one of these superhero movies the hero turned to the stunned civilians and went,

"Cover your ears and brace yourselves!"

"Why?"

"I'm about to punch this guy REALLY hard!"

Wiki sources:

http://en.wikipedia.org/wiki/Sound_pressure#Examples_of_sound_pressure_and_sound_pressure_levels

http://en.wikipedia.org/wiki/Noise-induced_hearing_loss

Edited October 12, 2013 by PTNLemay

[K^2]

Very rough estimates on some numbers I remember. A shock wave of approximately 1atm would result in injuries. That's about 1kg of TNT from 20 meters. That's about 4MJ of energy. For a nice heavy fist+forearm of about 4kg, this is equivalent to a little under 1,500m/s. So right around Mach 5. A punch at that velocity would produce a shock wave that's going to be lethal within about 10m and result in injuries to within about 20 meters.

[PTNLemay]

I'd like to learn the equations involved in figuring it all out myself, but that's definitely a good start. Thanks.

Oh, and the term I was looking for is "impulse sound". That's a quick sudden blast, like a gun shot or an explosive going off. As opposed to a long drawn out source like city traffic or a machine humming.

[DaveofDefeat]

Probly when there fist reached the speed of sounds would it start to hurt everybody else

[Jones-250]

When an irresistable force meets an immovable object, you can bet as shure as you live, something got to give. The same applies with two forces. In theory: If the punchers are tough enough there will be consequenses to the surroundings and/or to their physical structure. Matter is only that strong however... Thus, there is a theoretical upper limit, based on the materials of which the two are made, then their fists break apart.

Very rough estimates on some numbers I remember. A shock wave of approximately 1atm would result in injuries. That's about 1kg of TNT from 20 meters. That's about 4MJ of energy. For a nice heavy fist+forearm of about 4kg, this is equivalent to a little under 1,500m/s. So right around Mach 5. A punch at that velocity would produce a shock wave that's going to be lethal within about 10m and result in injuries to within about 20 meters.

Indeed. However, accelerating ones fist to 1,5k m/s in less than two meters... That should be an acceleration of 1 127 819 G. Good luck on that. Well, fiction does not have to make sense. That applies to eldritch supernatural science/magic as well.