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Homework Help: The Physics Behind a Bullet Hitting The Human Body

  1. Oct 10, 2012 #1


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    Ok so I'm trying to show how a bullet in real life will not actually make a person fly backwards like it does in movies. I have some idea of how to go about this but need help.

    So far...

    I know it's a perfectly inelastic collision since the bullet sticks into the person so would I have to use this? m1v1 + m2v2 = (m1+m2) v2f

    Or would I only be using momentum and/or force?

    v= 430 m/s


  2. jcsd
  3. Oct 10, 2012 #2
    Yes, you do have momentum conservation.

    Sorry, what do you mean? The momentum is certainly imparted to the shot person through a force, but you don't know either the magnitude of the force or the duration of time it acts on the person, do you?
  4. Oct 10, 2012 #3


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    No I don't know either of those values. Since I'm choosing a scene from a movie where this type of thing would happen, I'm not given any values. I just have to estimate the givens such as mass, velocity of bullet, mass of person and stuff like that and solve for everything else.
  5. Oct 11, 2012 #4
    The momentum imparted to the victim will be less than that imparted to the shooter by the recoil of the gun. Did that knock him down?

    I saw a training vidio once where they shot a guy wearing heavy body armor in the chest with several different high powered rifles, and a 12 ga deer slug. All this while he balanced on one foot. He just stood there and was not even close to falling down.

    I've talked with several snipers, and with people who were standing next to people hit by a sniper, and I've read the witness accounts. A heart shot causes them to drop like someone turned off a switch. A brain shot causes them to thrash around randomly for a little while. Any motion by the victim after being shot other than simply dropping is biological or neurological in nature.
    Last edited: Oct 11, 2012
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