Calculating Impact Force: Travis Struck by Object at Work

  • Context: Undergrad 
  • Thread starter Thread starter tarful
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Discussion Overview

The discussion revolves around the impact force experienced by a participant, Travis, who was struck by heavy tongs while working in the oilfield. Participants explore the physics of the impact, including the speed and mass of the tongs, and the potential energy involved. The conversation touches on the implications of such an impact on human anatomy and the difficulty in calculating precise force values.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Travis describes the circumstances of the incident, including his speed and the characteristics of the tongs.
  • Some participants suggest that the nature of the impact (glancing vs. direct) complicates the calculation of force.
  • One participant compares the energy of the tongs to dropping a heavy object from a significant height, indicating the severity of the impact.
  • Another participant discusses the concept of contact time and acceleration, suggesting that the impact force could be extremely high, potentially in the range of hundreds of g's.
  • There is a discussion about the kinetic energy of the tongs and how it relates to the energy transferred to Travis's face during the impact.
  • Travis expresses interest in understanding the potential force of the tongs for informational purposes, asking for formulas to calculate it.
  • Some participants provide formulas and suggest that Travis calculate the force himself, while others express skepticism about the usefulness of such calculations.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the exact impact force or the usefulness of calculating it. There are multiple competing views regarding the nature of the impact and the energy transfer involved.

Contextual Notes

Participants note the limitations of calculating impact force due to the complexities of the situation, including the nature of the impact and the crumpling effect of facial tissues.

Who May Find This Useful

This discussion may be of interest to those studying physics, particularly in the context of impact forces, energy transfer, and human anatomy in traumatic situations.

tarful
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IM000681.JPG

A few months ago I was at work in the oilfield. I was struck by some tongs along the right side of my face.

To simplify everything:

I was moving toward the tongs at 3mph. I am 6'1" and was struck by an object 3" thick around 5'6" off the ground. (my cheek) The tongs were moving around 70 mph and weigh in around 750 lbs. Let's assume they were right angles , no movement on my part (whiplash, absorbsion by neck movement).. just a simple answer of how hard I was hit in psi or impact force or whatever can be derived from the information I have stated.

Thanks in advance

Travis
 
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It's a trick question. If you were hit in the head by 750 pound tongs moving at 73mph, you could not post this question.
 
I posted a pic of me in the hospital. Lower jaw, upper jaw, orbital socket, nose and pallet were broken in at least one spot. Ending result is 7 plates and 53 screws.

So, someone can live through it. I just wanted to know what the worst impact could have been.
 
Yikes, I didn't even notice the pic attachment. I'm glad you're alive, tarful. Best wishes for your recovery.
 
Glad you survived, Tarful. I have to agree with Berkeman, though; it must have been a glancing impact, which would make it very difficult to determine how much force was actually applied to you. If it came straight at you, you shouldn't be here. Think of comparing it to someone dropping a bowling ball on your head from a second-floor window... the tongs would have had more energy than that by a long way.
I hope it's not too long before you can enjoy a steak again. :smile:
 
Been eating steaks for a long time. Well, about 6 weeks anyway. The injury happened June 9 2006 at 7:12 pm .. lol i don't think i'll forget that date.

So, what formula can I punch into find out what force those tongs had when they were moving. I just want to see the potential of those tongs. a lot of people have asked me how much force the tongs produce when they snap like that. I just wanted to see if I could give them an answer.

Thanks for all the kind words.
 
tarful said:
So, what formula can I punch into find out what force those tongs had when they were moving. I just want to see the potential of those tongs. a lot of people have asked me how much force the tongs produce when they snap like that. I just wanted to see if I could give them an answer.
Force is the the acceleration of an object multiplied by the mass of the object, or as we usually write it, F=ma.

Here is a wikipedia article to give you more information:

http://en.wikipedia.org/wiki/Force
 
tarful said:
I just want to see the potential of those tongs.
Now that Berkeman has shown you where the formulae are, we'll let you work it out for yourself. Leave it suffice to be said that I don't think many cars would have survived an encounter such as yours.
 
These guys are right - I don't think anything you can caluclate here would be at all useful. The kinetic energy of this object at 73 mph is equal to if it had been dropped onto your face from about 180 feet. That's a full dumpster dropped on you from ten stories.

Suffice to say, when it hit you, it simply knocked your face out of its way.
 
Last edited:
  • #10
Figure 2-3" of crushing and distortion of facial bones and tissues, and you're looking at 2-3 milliseconds contact time (you didn't slow the tongs down enough to matter too much in the calculation). 2-3 milliseconds to get you to 100 fps? A "square" hit gets you to the 1000 g neighborhood. 200 g is fatal (basal skull fracture) for race drivers w'out exotic head restraints built into helmets. Crush your head flat in 5-6 ms, and you're down to 400-500 g. Add a couple inches (and ms) for mashing your hard hat --- or did this give you an "uppercut?" You are one lucky roughneck.
 
  • #11
Yeah, I was thinking about that on my ride home - the kinetic energy of the tongs don't matter because that energy isn't transferred to your face. All you have is the energy of your head being accelerated to 73mph.

Your face acts like a "crumple zone" in a car here - the crumpling adds distance and therefore time to decrease the acceleration/ acceleration force.
 
  • #12
I'm back

"Your face acts like a "crumple zone" in a car here - the crumpling adds distance and therefore time to decrease the acceleration/ acceleration force."

That is what the doctors told me. I have been away for a while, work has been busy. I agree with your statements about my head being in the way of the tongs didnt really matter.

I finally got a copy of some xrays on cd, I'll show you the end result. It might take me a few minutes to convert to something I can post here.
 
  • #14
They're going to love you at airports. :biggrin:
Bloody hell! I haven't had that many screws since I got married. I guess future MRI's are out of the question.
By the bye, I believe that those are clamps, not scissors.
 
  • #15
renamed properly thanks

plates and screws are titanium.. so no worries at the airport :biggrin:
 

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