# Trying to use Newton's Third Law as a superpower

I'm trying to make a superhero that becomes as strong as he needs to be for whatever situation he's in; he supplies a reaction equal to whatever's acting on him. So if a car was coming at him with the force of x Newtons, this guy becomes strong enough to supply an opposing force of x Newtons and stop the car.

The thing is, the power works for stopping objects, but how would it work if he wanted to punch someone? It doesn't come under the same umbrella as Newton's Third Law, and he's essentially no longer supplying a normal force, and different punches are going to have different effects. I don't really want this guy to have a choice in how strong he gets - it's totally automatic. He's more immovable object than unstoppable force; would he still be able to fight properly?

Any ideas as to how he would work in a fight, or should he just be defensive?

Thanks.

• His name is Juggernaut. Commented Oct 29, 2019 at 3:18
• It may help to know that there is absolutely nothing special about the reaction force whatsoever. None at all. Its more accurate to say that forces come in pairs, one applied to each object, with the same magnitude and oposite direction Commented Oct 29, 2019 at 3:28
• It's all relative. If he imagines the bad guy's face as rushing to meet his fist then it's exactly the same as the stopping a car situation. Commented Oct 29, 2019 at 3:45
• In this case, the opposing force is... INJUSTICE! Commented Oct 29, 2019 at 9:07
• As far as I know - we are all such a superheroes everyday, everyfemtosecond. Newton third law is always working. If a car hits ANY person "with force x" this person also acts with force x at this car. ALWAYS. A car just have more mass and thus has a lesser impulse change. I thinks author should reformulate his question to be more phisicaly sound. Commented Oct 29, 2019 at 13:41

He could adopt some aspects of various martial arts and use his unique abilities to amplify the results.

Some moves I was taught long ago, in addition to the typical blocks and punches, involved combining knees and elbows as a part of some nasty infighting. The key to these moves involved pulling the opponent into a strike, like taking a punch, slipping it, grabbing the back of the opponents head and pulling it into your other elbow. Or in Muay Thai, grabbing an opponent and pulling them into a knee. It generates a scenario of "He attacked my fist (elbow) with his FACE". The Newtonian feedback should make the strike more effective, but hard to quantify.

Another tactic he may want to adopt is to put hard parts of his body in the way of incoming strikes. Things like ducking your head to take a shot on the top of the head rather than the face. The Newtonian feedback is going to make the attacker think they are punching a concrete column. Punching him in the head is going to break the attackers bones in his hand. That tends to take people out of the fight really fast. Shattered foot bones from a kick is kind of like natures way of saying "slow down".

So the fighting style will become like a nasty bar brawler that just wades in, relying on being tougher than anything being thrown at him.

• This is how I learned sabre parries. With a foil (poking weapon) you are moving your blade and pushing the enemy out of the way. With a sabre (slicing motions) you are building little walls where the enemy would like to go, right before they get there. Commented Oct 29, 2019 at 16:15
• Always better to be where the sharp thing is not :) Wing Chun is sort of similar with the very slight parries, shifting the incoming off target rather than a hard block. Commented Oct 29, 2019 at 16:28

Can he also be the Galilean Transformer? If he selects the right reverence frame, his fist isn't moving, his enemy's head is moving toward it. So, he stops the enemy's head (from his own point of view), and accelerates it dramatically (from the enemy's).

The Galilean transformation is a pretty helpful trick when working with Newton's laws, so it is still thematic.

• I'm a fairly new user, and so I'm not sure what the etiquette on this sort of thing is, and I appreciate the check-mark, but since your question has only been up for like an hour, is it possible to un-select my answer? It might be helpful from your point of view to give people a bit more time to come up with answers. It is fairly late at night in much of the US after all, you might see some more discussion if you wait until morning to select an answer. Commented Oct 29, 2019 at 4:24
• You are quite correct to suggest that, but in order for the OP to be pinged, you would need to frame the request using the "@user" format - or post the request in the thread of comments beneath the question. PS. 24-48 hours is the usual time expected before "the tick". Commented Oct 29, 2019 at 4:30
• @kaczmarek25 Please see my other post in this thread -- I'd suggest undoing the accept on my answer. That way you'll be more likely to get some other answers. Commented Oct 29, 2019 at 4:35
• Done and appreciate that, I'm a reasonably new user myself. Commented Oct 29, 2019 at 4:51
• Wouldn't the entire universe need to be moving in the direction of his fist (at least the side of the universe the enemy's face is on)? And if that's the case, then do the normal rules of Newton's third law still apply? Commented Oct 29, 2019 at 9:05