Why Doesn’t Iron Man Die Inside His Suit?

How Engineers Are Catching Up to Tony Stark

One of the things that makes Iron Man cool is that underneath his armor he’s just as human as anyone else, yet he can go up against beings as powerful as Thanos. The suit makes him nearly invulnerable, but how can that be? Even if the suit itself is indestructible, Tony Stark isn’t. The severe jerks he’d experience in his suit when he gets knocked around or changes direction mid-flight should still kill him. So why don’t they?

Before we can find the solution, we need to understand the problem. Newton’s third law of motion states that an object at rest will remain at rest unless acted upon by an external force. Likewise, an object moving in one direction will remain moving in that direction until acted upon by an external force. So if Iron Man was standing still and his suit suddenly started moving, his body would want to stay put inside. His body would also want to stay moving if the suit slowed down very suddenly from a high speed like this:

Both these cases involve extreme acceleration or deceleration. Since force equals mass times acceleration, a large acceleration corresponds to a…