Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Struck by object

  1. Oct 17, 2006 #1
    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
     
  2. jcsd
  3. Oct 17, 2006 #2

    berkeman

    User Avatar

    Staff: Mentor

    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.
     
  4. Oct 17, 2006 #3
    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.
     
  5. Oct 17, 2006 #4

    berkeman

    User Avatar

    Staff: Mentor

    Yikes, I didn't even notice the pic attachment. I'm glad you're alive, tarful. Best wishes for your recovery.
     
  6. Oct 17, 2006 #5

    Danger

    User Avatar
    Gold Member

    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:
     
  7. Oct 17, 2006 #6
    Been eating steaks for a long time. Well, about 6 weeks anyway. The injury happened June 9 2006 at 7:12 pm .. lol i dont think i'll forget that date.

    So, what formula can I punch in to find out what force those tongs had when they were moving. I just want to see the potential of those tongs. Alot 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.
     
  8. Oct 17, 2006 #7

    berkeman

    User Avatar

    Staff: Mentor

    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
     
  9. Oct 17, 2006 #8

    Danger

    User Avatar
    Gold Member

    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.
     
  10. Oct 17, 2006 #9

    russ_watters

    User Avatar

    Staff: Mentor

    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: Oct 17, 2006
  11. Oct 17, 2006 #10

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    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.
     
  12. Oct 17, 2006 #11

    russ_watters

    User Avatar

    Staff: Mentor

    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.
     
  13. Nov 21, 2006 #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. Nov 21, 2006 #13
  15. Nov 21, 2006 #14

    Danger

    User Avatar
    Gold Member

    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.
     
  16. Nov 21, 2006 #15
    renamed properly thanks

    plates and screws are titanium.. so no worries at the airport :biggrin:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Struck by object
  1. Power of an object (Replies: 11)

  2. Mass of an Object (Replies: 2)

  3. Colour of object (Replies: 11)

Loading...