Interesting physics statement...

[mzimmers]

I guess it depends on what you're shooting....

Heh...lots of bad posture and shooting form in that video. But, yeah, that thing must be a beast. I bet it's about 50% more recoil than a Weatherby .460, which is way past my comfort zone.

[virulosity]

Its true, the force is the same (neglecting windage losses). The reason you aren't injured when firing is because the pressure is not the same. Pressure is Force / Area. Just as you can hold a knife with a large handle surface area, yet stab through flesh with the very small area of the tip, a bullet has a small projected area in comparison with the grip of the gun.

[Interloper]

Way too much over thinking here.
Simple Newtonian physics:

-For every force there is an equal and opposite force. The energy carried by the bullet when leaving the barrel is 100% equal to the recoil of the gun.
The bullet will impart 100% of it's force on the target if it penetrates and stops. Less if it penetrates completely. If it ricochets (like the billiard ball) it imparts some of it's energy but carries the rest.
It really is that simple.

Of all the real experiences of people actually being shot that I have read, people often describe it as being punched. Some people describe the pain but no force, some people are not immediately aware they have in fact been shot. The notion of physically knocking someone over is pure Hollywood

[elSquid]

Way too much over thinking here.
Simple Newtonian physics:

-For every force there is an equal and opposite force. The energy carried by the bullet when leaving the barrel is 100% equal to the recoil of the gun.

"Momentum", not energy.

The bullet will impart 100% of it's force on the target if it penetrates and stops.

"Energy", not force.

It really is that simple.

One of my favorite engineering profs had a great saying: "There are only two things that you need to remember: f = ma , and you can't push on a rope."



Ok, it's a geek joke. Sue me.

-- Michael

[Boberama]

Theoretically true, but not true in real life.

It would take a lot more force to knock down the target, because the bullet's energy is not entirely transmitted to them in terms of motion in that direction. It may pass through, etc. And a round strong enough to knock someone down would blow through them.

It would take less force to knock over the shooter because the energy is transmitted through the stock to their shoulder.

It would be true if the bullet stopped on the target, and if the gun did not break the shooter's bones or fly away.

True in a physics text, but not in RL.

Send it to Mythbusters.

[Interloper]

Momentum is energy. Force is energy. What kind of grade did you get in that engineering class

[elSquid]

Momentum is energy. Force is energy. What kind of grade did you get in that engineering class

Momentum isn't energy. Force isn't energy.

Walk over to a wall; push on it. You've applied a force, but you haven't changed the momentum or the kinetic energy of the wall.

Walk over to a block on a frictionless table. Push on it: you are applying a force.

Force = mass * acceleration

The larger the force you apply, the more acceleration the block undergoes.

Once you stop pushing the block will stop accelerating; it will stay at a constant speed. At that speed, it has a given momentum and energy.

Momentum = mass * velocity

Kinetic energy = ( mass * velocity ^ 2 ) /2

-- Michael

[chim-chim7]

It's Newtons laws of motion. To every action there is a equal and opposite reaction.

[Interloper]

Dude, don't argue just to argue. You haven't said anything that actually contradicts my statement you're just doing the "herp-derp I was an engineering student pay attention to me BS".
Ignored..

[Cuda440]

When you fire a gun, you are really only controlling the acceleration of the bullet, which is much more manageable than a full speed impact. If you fired a 357 you would feel a healthy recoil. If you held that same weapon, and had someone else fire an identical 357 straight in to the muzzle of your own weapon, it would hit with a full 500-700 ft-lbs of energy and would possibly break you wrist or arm.

[elSquid]

Dude, don't argue just to argue. You haven't said anything that actually contradicts my statement you're just doing the "herp-derp I was an engineering student pay attention to me BS".
Ignored..

I admit that "Interlopian physics" is very compelling though.

If force is energy and momentum is energy

f = ke
p = ke

then logically

f = p

The advantage of this particular branch of physics is that there are no formulas to memorize and no need for any calculus. While there is no practical value to it - assuming everything is equal doesn't reflect the real world - it certainly does make final exams easy...



-- Michael

[DannyInSoCal]

The rule only applies to girly 9mm rounds. .45's defy all physical laws of nature...

[Exile Machine]

Saw a bad guy in a movie once got shot with a shotgun. The blast not only lifted him off his feet, it flung him ten feet across the room into the wall with such force that his body left a dent in the sheetrock. And not only that, the gun had such an incredible blast that it actually slowed down time.

-Mark

[Untamed1972]

Saw this on a pistol training DVD (Thunder Ranch, I think).

It's one of those things that's so clearly true, but I never thought about it enough to draw the connection.

If any round, fired from any handgun, was strong enough to knock the target down with a single shot, then the kickback would also knock down the shooter.

Equal and Opposite...

This issue was addressed in an episode of mythbusters when they were trying to test that hollywood notion of a guy being sent flying back when hit by a bullet. It took a 12g slug at fairly close range to move a pig carcass just a couple of inches.

A bullet simply doesn't have the mass to have the kind of effect on something that weighs 1000s of times more then the bullet itself.