If you get hit with a baseball or a bullet,
for God’s sake don’t rub.
You’re describing the difference in the concepts of ‘knocked over’ here. Standing people are precariously balanced. It doesn’t take much to knock someone over if they can’t catch themself and rebalance. For a person standing on the balls of their feet, draw a line from one foot to the other and apply some force at right angles, and they can be pushed off balance easily. A pig carcass is like someone sitting on the ground, it takes a lot more force to move something like that.
Answered to death already, but here is the simplest way of looking at it.
The resistance of the body to penetration is far less than the resistance of the body to being lifted off its feet.
You can test that on a shooting range.
Get yourself a (unfrozen) boneless roast, mark it with an X. Place it on something larger than a fence post(so it cannot roll off), and mark that with an X too. Line the X’s up.
Shoot it with something large calibre.
If it is still intact, I bet you it hasnt moved.
Couldn’t you just use a big glob of marmite instead of ruining a good roast?
Knock down is seen often enough with metallic silhouettes. A near-perfect inelastic collision, not involving animal propensities during trauma such like unconsciousness, weakening of the knees, losing one’s balance on the lurch, etc. Animal carcasses and cuts of roast have other uses. :rolleyes:
One of the things that made the opening battle sequence to “Saving Private Ryan” so stomach-turning and creepy was that it was the first big time Hollywood war movie I can think of that showed soldiers just dying and crumpling up, rather than flying backwards like acrobats, when they were fatally shot. It seemed, well, real, and it was one of the things that made it so horrible to watch. Which of course was the point.
Very few got knocked down in the Combat series too, as far as I can remember. But I do remember one film footage in Nanjing wherein Chinese men were shot by Japanese soldiers from behind with bolt action rifles: hands tied and kneeling, the bodied curving deeply forward from the force of the shot and the head snapping back, before they crumpled and slid down the ditch. So there, a possible knock down, had they been standing. But by unified rules, a man on his knees is considered knocked down. 
The first video that Fubaya linked to made the point that people who are shot are likely to fall over out of sheer reflex and reaction; just like if someone whipped out a pin and stuck you with it you’d flinch back and stagger in shock way out of proportion to the amount of force applied by a pin. Someone who knows what is coming and armored so they aren’t actually hurt, won’t.
I remember reading somewhere that the reason why people hit with an arrow, back in the old days, tended to go down was it was embedded in their mind that they WERE critically hit and SHOULD go down. Apparently, many arrow wounds were not that severe, or at least, immediately life threatening, but the psychological trauma of having that arrow and fletching sticking out of your torso was sometimes enough to make a man think he was in far worse shape than the wound produced.
Maybe when a bad guy in the movie sees that near half-inch hole on the end of that .45 spit a bullet at him, he tenses up like a cat and automatically springs backwards because he is SUPPOSED to.
Okay, time for bodies to be where the mouths are.
If you have been shot & survived, you do not have to play. All you other guys line up.
The set:
Boxing glove on a rod.
You must stand with eyes closed and ear plugs in.
You will be hit three times from an unknown direction & in some part of your body as a complete surprise.
First blow will be with a free swinging 5 pound glove & rod at 1000 foot pounds.
Next strike will be a 500 pound glove & rod free swinging at 1000 foot pounds.
Third time will be a .50 round from an WW2 P-47 machine gun ( just cause it is my test & I loves me some P-47… ) into one of several steel plates taped to your body so there will be no penetration or give. The shot will be straight so there is no glancing blow.
Once again, no sound or visuals, complete surprise.
Who will stand up for science and do this?
He he he
Seems 12 Ga. bean bags knock folks down? Because they do not penetrate??? Or?
If a man can stand with armor & laugh at '50 Cal pistol ammo, what size is need to knock a prepared man down against his will? What energy at say chest level assuming no penetration?
What size object with a point like a 20 mm canon or a 30 or a 40 would be needed to knock him over even though there is penetration?
Little skinny guy balancing on one foot vs big ugly Chicago Bears nose guard really planted on 2 feet and ready for it?
Get those calculators out guys, I be real curious…
I like the way they put up their hands to ward off the bullet when they know they are really going to get shot.
I can just see Bambi’s daddy getting blown sideways through a plate glass window…
Hey, even Superman used to duck when the bad guy threw the empty gun at him.
There are cases where people have seen a shooting and described how the victim flew several meters, and in the court when they have seen the security video, they have said it’s a forgery 'cause the victim just falls down.
People really should be more suspicious about Hollywood.
Scene: A snitch is lured into an abandoned garage, suddenly the lights are turned on and he sees six gangsters with Tommy guns and the capo he betrayed. The gunmen spray heavy .45 caliber bullets for half a minute ( that’s several thousands of them and who knows how many kilograms ) and the snitch just wriggles in one place.
After the shooting stops, he just slowly sinks down to his knees heavily breathing. Then the capo shoots a single shot between his eyes with a .22 caliber pistol and the snitch flies across the room.
And no-one in the production team saw nothing wrong with that.
And why nobody who’s stabbed with a pencil never flies across the room? The tip is like a bullet, right? You just hit very hard and…
Freakenstein, is that actually from a real movie? Which one?
Chronos
Ok, I’m not sure if I have ever seen exactly that, but many times something similar on TV. In many productions machine guns seem to be quite ineffective compared to pocket guns.
Chronos.
Just to clarify: the ‘scene’ is just a composite. But I’m sure I have seen lots of movies and TV episodes where both types of guns are used in separate scenes with described outcome.
( I should have written: no-one in the production team sees ( or will see )…
But I wouldn’t be surprised if there really is such exact scene somewhere.
But this is exactly why bullets don’t knock people down - because they DO penetrate. Bullets suck at transferring their momentum to flesh. If you do figure out a way to transfer all the momentum from a bullet to a body, then you’ve probably also made the shot non-lethal as you’re using all the energy to push instead of to penetrate and tear to shreds.
FWIW: I’ve never seen someone killed in person - let alone from a firearm - but there is a famous clip from D-Day in Normandy where what appear to be UK troops are disembarking and running up the beach and one is hit and drops like a sack of flour. Drops right down, not forward, not back. He was running forward when he was hit and there was very little forward momentum, he just dropped more or less vertically…literally all the life and energy left that body in that instant. It could be he tripped, but his movement was not natural: it was more the fall of a dead weight. The clip is played constantly in WW2 documentaries so some here have probably seen it as well.
Edit: just found it here: http://www.history.com/videos/d-day-allied-invasion-at-normandy#d-day-allied-invasion-at-normandy at 1:23 in the video, he will be the running man on the left side of the frame.
The fact that bullets penetrate doesn’t make all that much difference. A bullet that ricochets off of a steel armor plate will impart more momentum to the target, true, but only by about a factor of two. So if the shooter can shoot two guns at once without being knocked over, then the shootee can take a bullet to a steel armor plate without being knocked over, too.