Now then, let’s get some things straight. In all situations unless otherwise stated, we’re assuming regular Earth physics apply, and the weather was a perfect 20 degrees Celsius and zero humidity. We’re going to do our best here with limiting the use of “but the suit has xyz part to overcome problem abc” which is a pseudo excuse to make it better. In some situations, we can actually see a part doing a specific job, so we’re counting those as valid, however if something isn’t visible, and is assumed to be in the suit, then we can’t count that.
Stick the Landing!
Let’s start with something we see Tony doing all too often: Slamming down, usually in the pose that’s shown in the featured image (he’s taking a knee, and fist to the ground). Usually he does this as he comes down from flying somewhere, so first we need to use our lovely friend F=MA, to calculate the force in which he lands with. Why does that matter? Well, the age old phrase of “it’s not the fall that kills you, it’s the sudden stop at the end”. Tony is flying around at a few 100 km/h, and in some cases breaking the sound barrier. Let’s assume that Tony is 100kg, which is roughly 220lbs, a moderate muscle build for his height, since we know he works out but is far from a beefcake. Calculated out, that means that the force being applied on an object of his size is 34000 Newtons of force. That’s more than Spaceship One uses during takeoff. Even at Max Q, the term defined as “The maximum dynamic pressure at which aerodynamic stress on a vehicle in atmospheric flight is maximized”, meaning the highest amount of stress a vehicle can withstand, is peanuts compared to the force that Tony is receiving during the stop. Needless to say, the sudden stop means that Tony will not survive the sudden stop, nor will any of his organs inside his body. Physics says Tony Stark is dead.
What about that flight system he has though? Those various rockets all over the suit,, like foot, hand and back mounted rockets? Well, those hand/boot rockets are probably the worst body part to put things like that on. Tony flys at 340m/s in most situations, which is the speed of sound at sea level. To get to the speed, you’d need to have a rocket push out 200 kg of force per second, which is actually quite small given that rockets these days are pushing ~120,000kg/s. Why is it so bad when we obviously don’t need a powerful rocket? Well heat for one – Titanium and Gold alloy as referenced in the first Iron Man movie as what Mark 2 was made out of doesn’t absorb heat very well. There’s a reason why cooling is usually done with Aluminium and Copper. Gold actually has a very low melting point too, so his suit would melt off. Let’s assume that the rockets were “cold thrust” rockets, for some reason. The force applied on Tony’s joints in his legs, and hips, would send his femur up through his hip and into his chest cavity, killing him instantly. Only if Tony had solid struts to absorb such a force across the entire suit would this work, but we see Tony bending his knees and walking and what not, so we know there’s no solid strut there. Physics says Tony Stark is dead.
Taking a beating!
I’m sure that Tony is a tough guy and can take a few knuckle sandwiches to the face and walk away.. but what you can’t walk away from is getting hit by is a 50 kg weight on a bench press pole hitting you upside the head from another Iron Man suit. The calculated force on that is staggeringly high. Tony Stark in an Iron Man suit can lift 100 tons, so presumably he can also swing an object with that much force, so long as the object doesn’t weigh 100 tons. Calculated out means we’re sitting at just under 890,000 newtons of force. That’s about as much force as 8 F-22 Raptor fighter jets hitting you at the same time. No amount of iron plating or alloy that would be carryable by a machine assisted exoskeleton suit, could withstand such a force and “shake it off”. Physics says Tony Stark is dead. Really really dead.