Can we all admit that Tony Stark catching a bullet from the Winter Soldier’s gun was the coolest part of the latest Captain America: Civil War trailer? OK good. Now what would that feel like?
We know what the destructive power of a gun looks like, but quantifying that power, what it is, is trickier. One way of estimating how much punch a pistol or rifle has is to calculate the energy of a bullet coming from that gun. Kinetic energy — a product of a moving object’s mass and velocity — is a value that can compare the “power” of many different kinds of firearms.
From the trailer, it looks like the Winter Soldier is firing a 9mm handgun right into Tony’s hand. Take one half the average mass and the squared velocity of a 9mm bullet, multiply those together, and you get its kinetic energy: around 520 Joules.
But what does that feel like? The great thing about a general value like kinetic energy is that you can take the masses and velocities of other objects and compare them. Do that, and you’ll find that catching a bullet (assuming it doesn’t penetrate the hand) is like bare-handing a baseball going 190 miles per hour. Or imagine putting your hand in front of a golf ball about to be teed-off at 340 miles per hour. Ouch.
If Tony caught the bullet at the base of the palm, it would definitely hurt like hell, but he’d be fine. Baseball catchers repeatedly grab 110-mph fastballs without catastrophic injury after all. What if he caught the bullet higher up, near the fingers? Well, it turns out that the fastest Jai alai ball has the same kinetic energy as a 9mm bullet. And those players suffer wrist injuries — sometimes broken wrists — all the time. Tony is taking a serious risk.
However, knowing Tony, that fancy little glove probably had some vibranium in it to deaden the impact, or a design that redirected the force, or some other sci-fi hand-waving. The real problem – putting your unprotected hand over the chamber of a firing gun. That can remove fingers; the MythBusters proved that. Not so smart Stark.
Kyle Hill is the science editor at Nerdist Industries. Follow on Twitter @Sci_Phile.
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