Recoil when throwing at superhuman speeds.

Simple question: Superman picks up a Tungsten carbide javelin, (basically a modern Armour-piercing fin-stabilized discarding-sabot round without the discarding sabot) and throws it with full super strength so it's going at least 5,200 feet per second, the Muzzle velocity of the Rheinmetall 120 mm gun used on the M1 abrums.

Simple physics tells us that you throw something with X force, X force acts back on you which is why guns recoil. But here we have the force being focused onto one part of a human body, the arm, that can not be broken or sheered off, because super man.

So, what happens? Only thing I can think of is that are super person, (assuming our super is just "a brick" not a "Flying Brick") is going to spin like a top if they try to throw laterally, and crack the earth if they throw upward, maybe pitching themselves sideways.

This is probably something I'm going to hand wave, but I'm morbidly curious what would likely happen. Thoughts?

It's not like a tank firing a sabot round, where the projectile accelerates from zero to 5200 fps due to the explosive force of a gunpowder charge. It's more like a catapult or a trebuchet where the acceleration happens more gradually. And it's not just his arm; a baseball pitcher throws a fastball using his entire body to provide leverage. The flexibility of his body would allow him to absorb the recoil impulse. At worst, I can see him skidding backwards a foot or two, depending on how much traction his boots provide.

Anywho, you said it yourself: Because Superman.

edited 15th Nov '15 5:26:14 PM by pwiegle

catapult or trebuchet accurate slowly, but the speed is nowhere need 5200 feet per second. Where talking something like three feet to accelerate to top speed.

the problem is the recoil is focused on the hand(i know what you said about the whole body, but the projectile is being lunched from this location so the recoil should be coming back from here), and other then the super strength this super in question is still bound by the laws of physics. She can't, for example, lift a tank because A: she would sink into the ground, and B: she can't get a good point of leverage to do so unless she stood directly under it so she would just end up pulling her self down rather then the tank up. IN this world the required secondary super power to pull that off is flight or some equivalent to "hold" your self in place. Other wise you tend to bounce off things when you punch them at full super strength due to newtons law.

Because said throw is not directly inline with your center of mass, (that said now that I type this out a bow could be such aligned meaning that perhaps it would work out much better) the recoil would be directed on you at an angle, spinning you around. Super strength and endurance keep you from flying apart but you are still getting force pushed on you at a oblique angle and with your arm as a lever, I have trouble seeing how your not gonna spin like a figure skater.

the more i type this out the more I think I'm gonna hand wave it: still, I kinda want to know what I'm gonna end up hand waving.

I admit I don't know enough about physics to give you a good analogy, but never mind. If you're writing a fairy tale, don't quibble over talking bears.

Throwing is inherently recoilless. Recoil is generated in a firearm or a rocket by gas pressure pushing back. What is pushing back in this scenario?

Recoil is provided by the action/reaction pairing - gas and projectile launched in one direction, launch platform pushed in the opposite direction.

There doesn't need to be gas ejected to cause recoil - a coilgun that launches projectiles by using magnetic fields to accelerate them still has recoil even though there's no "gas pushing back" against it.

Because you've substituted gas pressure for magnetic force. That doesn't make your argument more valid, just different.

Throwing doesn't have that either. Throwing is the shot cup in a shotgun; it's the sabot in a sabot round. They experience no recoil in relation to the actual projectiles but nonetheless move them differentially. The forces in the system are all going in the same direction and are all equal, but the ranges of motion, and weights are different, which is why one of them goes flying away and the other doesn't.

edited 16th Nov '15 4:13:47 PM by Night

So, you're floating around in a space suit in orbit around the Earth - freefall, no air resistance - maintaining a constant distance from the space craft you've just exited.

You take a ball from your pocket and throw it in the opposite direction from the space craft - i.e. ejecting mass.

According to you, your position relative to the space craft won't change at all because "there is no recoil when throwing".

You have ejected a mass at a velocity - action - it doesn't matter if that mass is propelled by gas, electromagnetism or your arm: you have an action, so there is a reaction - "recoil".

BTW:

Your words regarding the origin of recoil.

edited 16th Nov '15 5:40:33 PM by Wolf1066

According to Skallagrim at Youtube, crossbows "recoil forward". I assume it's because the bow part is also thrown forward when they shoot, with greater force than the actual recoil from the bolt, while staying attached.

To throw something at a certain speed, you need to get your arm moving at the same speed and let go. I think what happens is that during the throw you push against the ground, which is the recoil that happens before the launch, and then your weight prevents the throw from becoming a jump.

but if your throwing with enough force to over come the resistance of your own weight. . . it's a one man Fastball Special.

edited 21st Nov '15 11:45:42 AM by dragonkingofthestars

If we're talking about Superman specifically, I always considered that his "Flight" ability actually comes with "locking himself to specific place and staying there, while airborne or not" function.

So any time he strikes downwards thus having no (how do you say "point of support" in English?), he's not propelling himself upwards, but is sending bad guy down.