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Even though I am quite confident in my believe that a free falling bullet would not penetrate my skull,
I am not willing to stand at the base of the Empire State Building and have people drop pennies on my head.

Charles L. Cotton wrote:

ScottDLS wrote:

Charles L. Cotton wrote:

Charles L. Cotton wrote:

LoneStarTx wrote:

The Wall wrote:They had this on Myth Busters. Basically they showed that if you shoot straight up into the air it won't kill you. If you shoot it at an angle other than straight up it could have enough velocity to injure or kill depending on the angle. Not something anyone should be doing regardless.

Sorry but that is just a tv show. The physics say otherwise. The bullet will free fall to terminal velocity with more than enough energy to penetrate the skull. Remember the advice that a penny dropped from a tall building can kill? Any bullet is much heavier and will fall from greater height.

You may be right, but do you have a formula to calculate the energy at various bullet weights? I recall the Myth Busters episode and if I recall correctly, the rounds barely cracked the dirt that appeared to be something in a dry river bed.

Chas.

Well, I found this but it's Greek to me!

Chas.

This is the formula for Terminal Velocity in a vacuum. Hence it only varies with the height and gravity. In a vacuum the bullet would return with exactly the same velocity as when fired (if fired perfectly vertically at < escape velocity). This ignores friction of the atmosphere, which practically limits falling objects to about 120fps if they don't have any downward velocity to begin with.

The bullet or the penny will be highly unlikely to penetrate the skull with their vertical velocity.

While I don't work as a Physicist...I DO have a degree in Physics and ballistics was within my course of study...

Okay, now we're getting somewhere. Using 120fps as the velocity in the muzzle energy formula of (V2/450,000)*Wt. we get (14,400/450,000)230=7.36 ft/# energy for a 230gr. 45 ACP. The impact energy would be half that for a 115gr 9mm round. I don't see those figures as allowing the projectile to penetrate a skull.

I bet this is less energy than the muzzle energy of a Daisey Red Rider BB gun. I think I'll try to find the velocity and BB weight to calculate this number.

I still don't shoot in the air to celebrate, but I'm curious about this falling bullet theory.

Chas.

Charles - The weight of the bullet is only one factor in the equation.
The velocity it comes down is effected by the height of the trajectory, the shape of the bullet and whether it is tumbling or coming down nose first.
I suppose if you ignore the effect of drag due to the atmosphere and shape you could come up with a "worse case" scenario.
Of course I don't shoot in the air either. I am also curious, but it's also hard for me to believe that it could be fatal.
I remember duck hunting one morning where a bunch of yahoos were shooting at ducks a mile away and my friend and I were getting rained on with lead shot.
They kind of just plopped down in the surrounding water like heavy raindrops.

Charles L. Cotton wrote:

Charles L. Cotton wrote:

LoneStarTx wrote:

The Wall wrote:They had this on Myth Busters. Basically they showed that if you shoot straight up into the air it won't kill you. If you shoot it at an angle other than straight up it could have enough velocity to injure or kill depending on the angle. Not something anyone should be doing regardless.

Sorry but that is just a tv show. The physics say otherwise. The bullet will free fall to terminal velocity with more than enough energy to penetrate the skull. Remember the advice that a penny dropped from a tall building can kill? Any bullet is much heavier and will fall from greater height.

You may be right, but do you have a formula to calculate the energy at various bullet weights? I recall the Myth Busters episode and if I recall correctly, the rounds barely cracked the dirt that appeared to be something in a dry river bed.

Chas.

Now I found this: http://www.madsci.org/posts/archives/20 ... .Ph.r.html

Forget I asked!!!! There's a reason I'm an attorney and not a physicist. I don't shoot in the air to celebrate anyway.

Chas.

The thing that people tend to forget it that the terminal velocity is not just a function of the weight of the bullet [or any other object] falling through the atmosphere.
As the equations shown in the link that Charles provided, drag is an important factor in calculating terminal velocity.
Also one has to remember that velocity is not the only factor to consider when trying to determine damage to a person hit by an object.
That said, I don't accept any show from the Myth Busters as a scientific fact or final word on any topic.
While they do some testing, their experiments don't have the rigor required for a true and valid scientific test.
As someone stated, they are just a TV show, whose purpose is entertainment.
Disclaimer: Unlike Charles I am not a lawyer, but that doesn't prevent me from expounding my legal views on this forum.

loktite wrote:

LoneStarTx wrote:

The Wall wrote:They had this on Myth Busters. Basically they showed that if you shoot straight up into the air it won't kill you. If you shoot it at an angle other than straight up it could have enough velocity to injure or kill depending on the angle. Not something anyone should be doing regardless.

Sorry but that is just a tv show. The physics say otherwise. The bullet will free fall to terminal velocity with more than enough energy to penetrate the skull. Remember the advice that a penny dropped from a tall building can kill? Any bullet is much heavier and will fall from greater height.

Perhaps in a vacuum ....

There would not be a terminal velocity in a vacuum, so the velocity would be much greater.
But, we don't live in a vacuum. At least some of us don't.

sugar land dave wrote:This is why I was home under my roof during NYE. In Sugar Land you could hear many gunshots for several hours. What goes up does come down in most cases.

I was astounded by the number of gunshots that I could hear on NYE.
They started around 8PM, I thought that people in my area had better sense.