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Let's say that a character moves much faster (>100 x) than a bullet.

If he is shot at, could he theoretically catch the bullet (and put it in his pocket) ?

  • What happens when he touches the bullet, does it burn ?
  • Where does the kinetic energy of the bullet go ?
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    $\begingroup$ What's more interesting is that this guy could also move several times faster than the fastest planes and would get the skin "air-burned" off his arm as he moved it through the air. $\endgroup$ – Hosch250 Sep 4 '18 at 20:23
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    $\begingroup$ "Speedsters" are regularly discussed here on Worldbuilding SE (although I'm not sure if specific aspect of bullet-catching was). Basically, the answer to you your question will depend on how much away you want to move from real physics and biology. $\endgroup$ – Alexander Sep 4 '18 at 20:32
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    $\begingroup$ @Hosch250, he might need an anti thermal body suit. $\endgroup$ – Tyler S. Loeper Sep 4 '18 at 20:39
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    $\begingroup$ A lot of the answer relates to the nature of the person's super-speed. For example, in The Flash, he is connected to the "Speed Force" -- a metaphysical energy field that permits him a number of related powers. I believe Flash can manipulate the Speed Force to essentially suck the inertia out of a moving object and slow it down; but of course at this point the physics is really magic wearing a "science" costume. $\endgroup$ – Stephen R Sep 4 '18 at 21:47
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    $\begingroup$ @user535733 You tagged this as a duplicate of a questions that is itself a duplicate of a closed question. Dereferencing the duplicate pointers, this question is nothing like the closed question, so I can't vote to close. $\endgroup$ – kingledion Sep 4 '18 at 22:04

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Assuming the Required Secondary Powers, certainly.

The superhero in question is capable of running at 100 times the speed of a bullet. For simplicity's sake, we assume that the bullet is a standard 5.56x45mmNATO round travelling at approx. 1000m/s.

Since most depictions of heroes with superspeed show them doing everything like normal humans, except faster, we can assume that we can scale up normal human mechanics to model the superhero, and that the superhero is equally durable on all parts of their body.

According to research into the patterns and speed of foot-strikes during running, the speed at which the foot strikes the ground (Vz-limb) is approximately 1/3 that of the horizontal running speed. As a result, the superhero's feet strike the ground at approximately 33km/s, almost triple the escape velocity of the Earth and at the upper range of meteor impacts.

At these speeds, the superhero's feet must be able to withstand forces equivalent to that of a meteor hitting them with every footstep. If the superhero can perform daily tasks such as running or climbing at such speeds, the energies imparted by bullets would be negligible compared to the literally astronomical energies that the superhero deals with on a daily basis.

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    $\begingroup$ I once tried to write a story where people got superpowers without any secondary superpowers. It did not end well for anyone afflicted with a superpower. $\endgroup$ – Joe Bloggs Sep 6 '18 at 7:52
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    $\begingroup$ @JoeBloggs Sounds like several episodes of "what-if". $\endgroup$ – Martin Bonner supports Monica Sep 6 '18 at 7:59
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    $\begingroup$ You're not wrong, but if he's fast enough to run at 100x the speed of a bullet, he can also presumably just run at the same velocity as the bullet, in which case grabbing it exerts essentially no force on him anyway (since the velocity difference of the collision is zero, aside from the slight impact of his fingers clamping down on the bullet, which would be the same as if both he and the bullet were at rest and he picked it up off of a table, for example.) $\endgroup$ – reirab Sep 6 '18 at 16:31
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    $\begingroup$ To get a good mental picture you can try scaling the bullet speed down instead of scaling the running speed up. If maximum human running speed is roughly 10 m/s, and the bullet moves 100 times slower, then the superhero experiences the bullet as if it were moving at mere 10 centimeters per second, or 20 feet per minute. $\endgroup$ – 2012rcampion Sep 7 '18 at 4:30
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    $\begingroup$ @Upper_Case Yes, but if he grabs it while running at the same velocity as it, stopping it or changing its trajectory becomes completely trivial relative to what is required to stop or change his own trajectory. If he can reasonably control his own direction and speed at 1/100 of his top speed, the difference to also control the direction and speed of a bullet he has grabbed at 0 relative velocity will be almost unnoticeably small. $\endgroup$ – reirab Sep 7 '18 at 23:54
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If you were fast enough to have coordinated movements, yes you could catch a bullet.

Simply grab it and slowly push against it until it slows down and it is stationary in your hand. Your approach would be kind of like how a trampoline catches a falling object, by gradually slowing it down. You would not simply stand still and let it pass through your hand as that would be the same as getting shot; just much slower from your perspective.

If you are fast enough to do this slow-down procedure reliably, then I can see no reason why it would not work. A bullet after all is not very massive.

The final consideration is inertia. I think for impact bullets rely a lot on inertia from your body to achieve penetration; aka your body resists getting pushed back until the bullet is already inside you. If you can move around at 100x regular human speed, I imagine that inertia is no longer an issue. So bullet catching should be no problem.

There is some associated physics for how much energy you would have to use. I believe it is covered in Hooke's Law.

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    $\begingroup$ The bullet will still be hot enough to burn, but not a terribly severe burn. $\endgroup$ – John Sep 4 '18 at 21:21
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    $\begingroup$ @John I double the bullet would have any meaning full time to transfer any heat energy to the speedster. Your average bullet travels at 2500 feet per second. Assuming your arm was 3 feet long, you would have 0.0012 seconds of contact to stop the bullet. I doubt that is enough time for the bullet to transfer any meaning full heat energy to your finger, which just broke the sound barrier as well... $\endgroup$ – Shadowzee Sep 5 '18 at 1:43
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    $\begingroup$ @John friction down the bore won't generate that much heat, if you are thinking of that causing the burn. What will cause the burn is the rotational energy that also has to be expended. Rifled barrels rotation to the bullet, anywhere from 1 revolution in 4 or 5 inches of forward travel up to 24 or even more (patch-n-ball muzzle loaders are 1:36 or even 1:48). 45acp, a nice big slow bullet is 1:16 standard, at a 900 fps muzzle velocity it is rotating at just over 40,000rpms. Now imagine a rifle at 1:12 and a muzzle velocity of 3000fps.... $\endgroup$ – ivanivan Sep 5 '18 at 1:43
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    $\begingroup$ I once saw an electrical engineer float a ball bearing in a rotating magnetic field and try to touch it. The now rotating ball bearing took off at significant speed and put a hole in the drywall. The conversion of rotational inertia to good old fashioned velocity could be problematic, but can be handily dealt with by the hypothetical speedster encouraging the bullet to 'spin out' from his hand several times. At the least it should be fairly easy to make it miss any live targets. $\endgroup$ – Sean Boddy Sep 5 '18 at 2:11
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    $\begingroup$ @John If the speedster could travel 100x the speed of a bullet (Isn't that something ridiculous like 200x the speed of sound?) they need some secondary powers to hold their body together. Unless its like quick silver from the new x-men films $\endgroup$ – Shadowzee Sep 5 '18 at 4:42
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Not as you imagine. Or at least, not without additional powers.

The issue is not only being able to move the hand to "catch" the bullet. The main issue is to decelerate it until it stops.

You move your hand extra fast and get to catch the bullet? Well, the bullet continues at full speed, and (unless you move your hand away) continues through your hand, as it would do with any normal person, because the human skin is not strong enough to decelerate the bullet.

With this approach, the only benefit of superspeed is that you get to chose which part of your body you will use to slow the bullet (or, more sensibly, of getting out of its way).

So, -barring an additional superpower of superresistant skin, or that your character has some armor and padding to put in the bullet's way- you need to move with the bullet in order to decelerate it gradually.

I have no data of how much pressure the human skin may resist before breaking, but that (and the surface of the bullet, to determine how that pressure can be converted to energy) will determine how fast the bullet can be stopped and how long your hero will have to run (with the bullet in his hand) to stop it safely.

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    $\begingroup$ It feels reasonable to assume they have super skin. Otherwise, when they move 100x faster than a normal person, they'll peel themselves like a banana under the forces. $\endgroup$ – Cort Ammon - Reinstate Monica Sep 4 '18 at 21:34
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    $\begingroup$ @CortAmmon Not to mention shattering all their bones under the acceleration. $\endgroup$ – Shufflepants Sep 4 '18 at 21:56
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    $\begingroup$ If he can move 100x the speed of a bullet, then he can move his hand 100x the speed of a bullet, and so he can stop his own hand after it is moving 100x the speed of a bullet. If you can stop your hand you can stop a bullet which has far less rest mass. $\endgroup$ – Shufflepants Sep 4 '18 at 21:59
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    $\begingroup$ @Shufflepants that is a very nice way of explaining that such assumption is reasonable. $\endgroup$ – SJuan76 Sep 4 '18 at 22:07
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    $\begingroup$ I'm not going to downvote but I think this answer is wrong. If he can slow down his body then he can slow down his body holding a bullet. The real problem is getting up to speed without exploding. Most bullets are supersonic. $\endgroup$ – workerjoe Sep 5 '18 at 0:42
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Yes

Could he theoretically catch the bullet (and put it in his pocket) ?

Absolutely. Let's assume he's running at the same speed of the bullet. He reaches out, grabs the bullet, puts it in his pocket. Since the bullet is going the same speed as before, the only difference is the energy put into changing its vectors, which are next to nothing.

Why would this work? For the same reason that two relay runners can hand a baton between them. The forces involved at the moment of the hand-off are minimal because everything's moving in the same direction at the same speed.

What happens when he touches the bullet, does it burn ?

It depends on how soon after leaving the muzzle of the gun it's taken. Remember that the bullet is slowing down with each passing moment, and it's cooling off, too. Grab it right out of the gun... hot. Grab it at the far end of its arc? Possibly too hot to hold comfortably, but not hot enough to burn.

It also depends on the size and nature of the bullet. For example, a .22 long-rifle bullet doesn't have a lot of bang behind it, so not as hot as the nearly .22 calibre bullet fired by an M16 combat rifle, which has considerably more bang behind it (those are two very different bullets, BTW). Likewise, the .22 shell is likely hotter than one made out of depleted uranium (given the same amount of powder behind them) due to the higher density of the depleted uranium shell. Basically, size of the bullet, shape of the bullet, material used to manufacture the bullet, amount of powder behind the bullet, etc.... it's a complicated question.

so, the best answer to this question is, "it depends."

Where does the kinetic energy of the bullet go?

So long as the runner keeps running it doesn't go anywhere. The bullet is still moving at the same speed it was before and has the same kinetic energy.

The problem is when the runner decides to slow down. Let's assume that's instantaneous. The bullet (and his shoes, eyeglasses, rings, piercings, wallet, etc.) all want to continue at the same speed as before. This is Newton's First Law, said simply, "an object in motion remains in motion until acted upon by another force."

What is that other force? If it's in his pocket, that other force is the strength of the fabric of his pants against the decelerating force of his body. In short, if he stops instantaneously, the bullet tears through his pocket and keeps going just as it would have had it hit the pants while hanging on a clothes line.

But if the deceleration is slow enough, then the kinetic energy is absorbed into the pants and body. If you throw a rock against a bag of flour and it doesn't pierce the bag... that's what would happen. The rock stops, the bag and flour absorbed the kinetic energy.

It's worth noting how important it is that your runner decelerate very slowly. If he stopped instantly, his wallet, which has greater mass than the bullet but has been acelerated to the speed of a bullet, would want to continue. It's big enough that it might not break the skin... but it would hurt something awful.

A very practical example of this is stomping on your brakes to quickly stop your car. Where does the energy of your upper body go? Into your arms and seat belt. If you didn't have them, it would go into your head as it bounces off your windscreen.

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  • $\begingroup$ fired bullets are very hot as anyone who has ever touched an expended round or shell can attest. bullet wounds don't cauterize because the bullet is (usually) not in contact with flesh for very long as it passes through. $\endgroup$ – Zack Sep 4 '18 at 22:54
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    $\begingroup$ @Zack, fair enough! I'll modify my answer, and thanks! $\endgroup$ – JBH Sep 4 '18 at 23:33
  • $\begingroup$ This is the best answer of the bunch. A lot of nonsense in the others. If you are at the same speed s the bullet, the only motion of the bullet relative to you is that it would be dropping due to gravity just like a bullet he was holding and released would. Likewise, if he grabbed it (let's say he carries an oven mitt for these situations), it would be no different from a bullet that he pulls from his pocket at speed. This is just Newtonian relativity. Most of the answers are making this far too complicated. $\endgroup$ – JimmyJames Sep 5 '18 at 15:48
  • $\begingroup$ The kinetic energy of a stopping upper body does not go into the arms and seat belt. Where specifically does it go? Into building building huge muscles? Breaking down the chemical bonds in the seat belt? I hope not. The energy goes into the brake pads, which get hot. The seat belt merely transfers forces. $\endgroup$ – Phil Frost Sep 5 '18 at 23:07
  • $\begingroup$ @PhilFrost, You're correct, I simplified the issue for the sake of brevity, but in the end all energy must come to a stable state somehow. But I felt it unecessary to chase the entire chain. If you want to do that, you have to continue with the heat transferring into the atmosphere and from there disseminating through gas until an equilibrium within the closed system of our planet is achieved. I felt the detail would distract from my point. $\endgroup$ – JBH Sep 5 '18 at 23:13
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What is the energy of a bullet?

The KE of a .38 Special, 125 pistol bullet is a about 300 J; one of the weaker handguns out there that you would reasonably expect to kill a man with. On the heavier end, the KE of a 30-06 180g is about 3950 J; this is a gun you would use on a moose.

.38 Special   125g   300 J 
 30-06        180g  3950 J

What if he catches it against his body?

The body's strength is mostly in the core and legs. If the man is really 100x faster than a bullet, but not mysteriously strong as well, it makes sense for him to use his core and legs to stop a high energy bullet.

Work is equivalent to force time distance. $$ W = f\cdot d$$ We can figure out the equivalent distance from calculating the force it takes to move an object. A football blocking sled has a resistance around 450 N (once it starts sliding, it takes a bit more force to get it going). Catching a pistol bullet is the equivalent of moving a blocking sled about 2 feet (2/3 meter).

A 30-06 rifle bullet, on the other hand, is equivalent to moving the blocking sled 9 meters; so if the very fast man caught it against his body, it would take quite a few steps to slow it down.

Can this rip an arm off?

I don't have any real good evidence for how much force it takes to rip an arm off, but the world bench press record is over 1000 lbs, which is 4500 N. 3900 J applied over a little less than a meter will would hit his mark. If the very fast man grabbed a 30-06 bullet with his hand, then tried to come to a full stop immediately, without letting the bullet travel farther than an arms length, the force applied to slow it down would be in that range. A bench press is two handed, so if he grabbed it with one hand, that would be a lot of force, and I'd guess pretty close to ripping and arm off. So for big rifle bullets, the very fast man will have to take several steps while holding the bullet to slow it down safely.

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    $\begingroup$ How exactly are you grabbing the bullet? Surface area will play a large role in determining if you slow the bullet down or the bullet simply punches through your hand. $\endgroup$ – chepner Sep 4 '18 at 21:06
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    $\begingroup$ @chepner No. if you are moving faster than the bullet, it's velocity relative to you isn't very large. Just run faster than it, push against it, and slow it down. Don't push against it so hard that it punctures your skin (or shirt). $\endgroup$ – kingledion Sep 4 '18 at 21:15
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    $\begingroup$ This is all sort of besides the point. You calculated how much energy the bullet has, but if you bothered considering the amount of energy that just his hand has when he's moving 100x the speed of the bullet, if he can stop his own hand, the amount of energy that he needs to dissipate for the bullet will seem trivial. $\endgroup$ – Shufflepants Sep 4 '18 at 22:02
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    $\begingroup$ "If the man is really 100x faster than a bullet, but not mysteriously strong as well" then he died a long time ago as a result of running at 100x the speed of a bullet. The compression heating, air friction, and forces required to accelerate his body at 100x the speed of a bullet are all orders of magnitude higher than what would be needed for him to catch that bullet safely. $\endgroup$ – reirab Sep 6 '18 at 16:52
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That depends on what you mean by really fast. If he had a fast enough reaction speed, acceleration, and hand-eye coordination, then sure - he could.

But the hard part isn't catching a bullet. Anybody can 'catch' one, though most people can only catch bullets with their abdomens. The hard part is slowing one down.

He would have to either wear an extremely thick pair of gloves, or slow down over a long distance. Unless your palms are Superman steel, you can't just grip it and come to a halt - that's the same as just being shot in the hand.

Instead, I'm imagining a guy like the Flash running alongside a bullet, and gradually pushing it backwards. It's the same as any impact - you'd have to lessen the force by extending the distance. Add a slight resistance (your hand) and reduce the energy slowly until it's slow enough to halt.

And yep, that energy gets converted into heat. Luckily a bullet's mass is small, though. It would definitely scold your hand - but I assume if you can survive the g-forces and friction of moving that fast, you could survive that.

Low caliber bullets probably wouldn't be as much of a problem, but a bullet from a long gun would take some slowing.

Rather than catching it, a much easier way would just be to deflect it. Use a hard surface and 'tap' the bullet on the side to knock it off-course from its target.

Either way, it's a phenomenal movement speed required.

Basically, if you want to catch bullets, you need to wear some seriously heavy duty gloves.

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A few searches suggest that a bullet leaves the barrel somewhere in the 200C to 300C range. That's hot enough to burn, but there won't be much time to transfer heat. Catching a bullet would have to be done very quickly, giving only milliseconds to transfer heat. Practically speaking, we should not expect the bullet to burn the character in this timeframe.

As for what happens to the energy of the bullet, it is going to have to get absorbed somehow. If the character is catching it similar to that of a baseball, we would expect most of that energy to get dissipated into muscles as heat. That's about 600J of energy, which is not much by human standards. It's on part with the energy required to climb some stairs. Your super-fast character, of course, would be capable of vastly more (because they have to move the body at fast speed anyways), so dissipating this energy should not be difficult at all.

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    $\begingroup$ That's about 600J of energy, which is not much by human standards. The issue is that those 600J are transfered through just a small portion of the skin. Stop the bullet too fast, and the tissues break, and you get a wound (which is in fact what happens when a "regular" person "stops a bullet" with his body). The guy would need to move at a speed comparable to that of the bullet to be able to slowly decelerate it. $\endgroup$ – SJuan76 Sep 4 '18 at 20:26
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    $\begingroup$ @SJuan76 That is the standard garden-variety problem with a speedster. Given that the OP already stated that the character could move 100x faster, I assumed that they had the biology it takes to survive moving 100x faster. $\endgroup$ – Cort Ammon - Reinstate Monica Sep 4 '18 at 20:46
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I assume he is shot at, i.e. he sees the bullet before it hits him. And I further assume his mental processing and nerve conduction speed are fast enough to react.

  1. yes, he can catch a bullet and put it in his pocket.

  2. The bullet will burn, but his fingers will already burn from moving through the air fast enough to catch the bullet. If he can deal with heat of his ultra-fast movements, he can deal with added heat of the bullet. Besides, he will touch the bullet for a relatively short period of time

  3. Kinetic energy will be absorbed by his hand and the rest of the body. Kinda like you absorb energy when you catch a baseball. He might have to move with the bullet or redirect it, kinda like that clip from Kung FU Panda where he "catches" a cannonball, or rather redirects it to spin around him.

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Yes, but not easily, and...

If you can move 100 times faster, then you can rather trivially move as fast or just a bit faster than the bullet as well. Unless your superspeed explicitly works on/off 100% or none (you didn't say so). That doesn't mean it's easy to do. This is approximately like trying to swat a fly not with a flyswatter (which has many little holes) but with e.g. a solid plank. Most of the time, you won't hit the fly because the air cushion that's in front of the plank pushes it away. Now, a bullet (without specifying what type) typically travels at a speed anywhere from 300 to 600 m/s. So your hand would necessarily be moving at around 600 or so m/s as well, which would not only mean a quite considerable air cushion, but also a supersonic bang. This adds to the complexity of actually catching it.

Would it burn or otherwise damage you? No. If you are able to move at said speeds, your body can withstand much greater stress, a puny little bullet is totally insignificant.

...and?

It wouldn't make sense to do it. Being able to move 100 times faster than a bullet would mean you can move at around 50 km/s, which rivals a meteor falling from the sky. So, not only are you apparently able to survive abuse which causes meteors made of rock to break up or vaporize, which means that you are basically invulnerable and really couldn't be bothered less than being hit by a bullet.
But also, if you are truly afraid of being hit, you can trivially deliver an air punch with your palm which instantly turns the air in front of your palm into plasma and which will deliver an immense explosion, not only stopping but vaporizing the bullet. That is, not just the bullet, but also anyone standing within 20 or so meters, including your attacker. People half a kilometer away will probably still be deafened.

Also, being able to move at such speeds, this means that your body can somehow invoke a really huge amount of energy, well... no idea how exactly, out of nowhere. Something around 60 gigajoules, if I got my math right. Which is kinda frighteningly awesome.

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  • $\begingroup$ [Today I Learned] - The Flash can perform Hadoukens. Awesome. $\endgroup$ – Ruadhan Sep 5 '18 at 11:13
  • $\begingroup$ I'd like to point out that not only air punching the bullet, but literally every movement this speedster makes at 100x bullet speed will result in death and destruction. Moving at 50km/s through the atmosphere at sea level, this answer suggests that a person (approximated as having the area of a 1m-diameter circle) will be subject to about 1GN of drag. (Which is then, of course converted to heat via some way or the other.) +1 from me. :) $\endgroup$ – Inarion Sep 5 '18 at 14:04
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Maybe

If a character is going to move impossibly fast, they're going to need a bunch of necessary secondary powers.

  1. If they're moving many times the speed of a bullet, the movement of their body/limbs will break the sound barrier unless some magic prevents it. This could have destructive effects on their flesh, which leads us to #2...
  2. They'll need to have superhuman toughness as well, because first, the air resistance would be destructive, and second, you'd have adiabatic heating as a result of air compression.
  3. They'd also need superhuman strength - you can't overcome inertia in an enormous hurry without it.

If this is all being dealt with using magic, then you also don't need to worry about the side effects of catching the bullet. If it's not being dealt with using magic, then you've already got superhuman strength and toughness to deal with the temperature of the bullet or dealing with its kinetic energy.

Edit: If the problem in #1 isn't dealt with magically, your character is going to be pretty loud when committing any feats of super-speed.

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  • $\begingroup$ For #1, there's an interview with Brian Singer about Days of Future Past where he discussed that. Something like "Even if you don't break the sound barrier, a human accelerating instantly to airplane speeds is going to be very loud. Barry Allen is the kind of guy who'd find a clever science way around that. Pietro is the kind of guy who'd always wear headphones. Which won't help anyone but him, but he's also the kind of guy who finds that funny." (But despite him saying that, in the movies, we don't see Pietro deafening everyone around him…) $\endgroup$ – abarnert Sep 4 '18 at 21:01
  • $\begingroup$ Pietro/Quicksilver also just wears goggles, which is a nice precaution but insufficient (My eyes! The goggles do nothing!) if he's moving as fast as he appears, so we have to assume "magic" for a lot of it, as with most mutant powers. $\endgroup$ – jdunlop Sep 4 '18 at 21:28
  • $\begingroup$ Another thing to take in consideration is their clothes and what they have inside the pockets, I imagine that even if you are superman at the moment you do a full stop from 100x bullet speeds your wallet, keys, phone and glasses would start going at that speed and just go flying and whatever was on your pockets would destroy your clothes, unless of course their superpower is to create a field that allows all matter to accelerate and decelerate. $\endgroup$ – draconk Sep 5 '18 at 9:04
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Yes, if they don't die in a bloody manner.

Ignoring how your superhero actually got that fast, the effects of the extreme acceleration on him, and how they sustain that movement, they will still probably succumb to a very bloody death if they don't have other protection.

People aren't particularly aerodynamic, and even an aerodynamically optimized shape would heat up considerably at those speeds, as well as undergo stresses flesh probably can't endure. Your hero would be burned to a crisp, as well as torn apart into bits.

In the end, ignoring all these aspects of the problem, if the hero can accelerate just as fast as the bullet, he can probably grab it and slowly slow down (heh), and he will be fine.

Or, given that he has super-reflexes and super-strength, he could just grab it without running.

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A hunting rifle has a muzzle energy in the neighborhood of 4000 J. A joule is a newton-meter, so if this character is to stop the bullet in the space of one meter (a reasonable definition for "catching", I think), a force of 4000 newtons must be applied to the bullet.

Wolfram Alpha provides a colorful comparison to put that in perspective: 4000 newtons is just a tad less than the world record human bite force. So catching this bullet is (at best) like being bitten by the world's best human biter, except with a bullet for teeth.

Possible? I suppose that depends on the explanation for why this character is so fast. Certainly the kinetics of the character's body also involve similarly high energies which are somehow survivable.

Does it burn?

Well, 100x the speed of a bullet is a speed similar to atmospheric reentry. Spacecraft do get pretty hot.

Where does the kinetic energy go?

Same as catching a ball: a lot of it gets transferred into the rotational velocity of the Earth.

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There are a couple of ways one might think of catching a bullet if you can move 100 times as fast. If by "move" you mean "run," you can run after the bullet and slow to 1/100 your top speed as you catch up, in which case the bullet will be just hanging there in midair (relative to you) for you to pick up.

Another way is to stand in one place as the bullet flies past you and grab it. If what you mean by the ability to move 100 times as fast as a bullet is that you can reach out at a speed of several times 10,000 meters per second, close your fingers, and pull your hand back toward you, without damaging yourself just by reaching out like that (even if the bullet never touched you), then your bones, muscles, and skin must all be amazingly strong to avoid being torn away from each other by this motion. Given the strength of the forces that must be holding each bit of skin to each other bit of skin, it seems reasonable to conclude that the bullet will be unable to separate your flesh enough to penetrate. It wouldn't even cause bruising, assuming that you didn't bruise yourself just by sticking your hand out so fast. Likewise you're impervious to the heat generated by compressing the air hypersonically as you move your hand through it, so the small amount of heat generated by the bullet's impact doesn't bother you either.

Eye-hand coordination at those speeds is another question. Better assume you have that too.

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One consideration is that the question needs to be better defined. Most pistol and all shotgun projectiles leave the barrel at sub-sonic speeds, that being around 1,087 ft/sec + or minus depending on air density. The world's fastest runner has achieved a speed of 28 mph or 41.07 ft/sec. Having 100x increase in ability could provide the speed but being able to more than double, perhaps triple the sound barrier would require much more super human endurance. As previously mentioned to eliminate friction and lack of aerodynamics to break through that sound barrier is a much bigger issue that reducing the inertia of the bullet.

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  • $\begingroup$ Welcome to the site. This is more commentary than an answer to the question. Using the comment function requires gaining some reputation via the site's mechanisms. As it stands this answer could get deleted if it is not edited to answer the question. SE is a little different from other forums/discussion boards. This site is all about getting specific answers for specific questions. Check out the tour and help center for more information on how the site works. $\endgroup$ – James Sep 5 '18 at 16:25
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Yes but not easily. He would also need something to cover his hand to prevent it from burning at the speed of movement and to prevent the skin from being ripped of when they touch the bullet.

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