Newton's Third: it's the law

Kevin Koch posts from his blog:

Being a former physics major has certain drawbacks. Oh, it’s a tremendous advantage in understanding how and why things move the way the do when I’m animating. But it makes it hard to enjoy some animation, when the most basic principles of physics are grotesquely violated. For example, why does the above look so wrong?

We intuitively know it’s wrong, and telling ourselves that Hancock is a super-powered dude doesn’t help much. Because even super heroes have to answer to Isaac Newton. Newton blew a lot of people’s minds by summing up much of the hows and whys of motion in three simple laws. And here’s his third law:

For every action there is an equal and opposite reaction.

Simple, huh? If I’m standing on the edge of a boat, and step towards the dock, the boat will go away from me as much as I go towards the dock. And if I’m not aware of this law, I end up all wet. If you’re sitting in a swivel chair, take that coffee mug off your desk, lift your feet off the ground, and throw the mug as hard as you can. Notice how you spin in the opposite direction from the throw? That’s Newton’s Third Law in action. Oh, and I hope you didn’t aim the mug at your officemate.

In the above clip, the law says that the force being generated at Hancock’s hands, which serves to propel an 80,000-pound whale around 600 feet in a split second, would have an equal and opposite effect at his feet. That’s assuming Hancock’s body, being super and all, is rigid and strong enough not to tear itself apart.* I’m not sure how deeply Hancock would end up burying himself in the sand, but it would be pretty deep. The whale actually wouldn’t end up going much of anywhere. Hancock would just corkscrew himself deep into the sand.

Here’s an experiment: go to an ice rink. Wear some slippery-bottomed dress shoes, pick up a very heavy object, go out on the ice, and see how far you can hurl said object. Just don’t blame me when you end up breaking your tail bone or your nose.

Of course, we’re assuming the whale above is pretty much petrified. Because if it isn’t, Hancock would simply pull two fist-fulls of flesh from the poor creature’s tail before that 40-ton mammal would budge more than a few feet. Try grabbing a big fat regular fish by the tail with a pair of pliers, and jerking it as far and as fast as you can. Yep, the fish won’t move much, but you will tear a little piece of tail away.

I know I’m being Johnny Buzzkill here, and that the filmmakers knew this was ridiculous, and that the animator was just doing what they were told, and it’s played for laughs, and all that jazz. My point is that, if you want the audience to enjoy the marvel of seeing a regular-looking dude doing something physically extraordinary, then the biomechanics and physics can’t be as trivial looking as an actor tossing a 30-pound prop, like this:

Otherwise, why bother to have the pavement exploding when Hancock lands after a huge jump? It’s kind of like watching bad Japanese monster movies, where some 120-pound guy in a suit jumps around and pretends to weigh 100 tons, but they still move like a gymnast in a rubber costume. It just looks dopey, even when the miniatures of the city being stomped to pieces look pretty good. Call me a curmudgeon, but a cursory nod to physics, even extremely exaggerated physics, make these kinds of scenes a lot more fun for me.

*Which is what would have happened to good ol’ Lee Majors, the Six Million Dollar Man, when he tried some crap like tossing a boulder with his bionic arm. The force generated at his hand would have an equal and opposite effect at the junction of his bionic arm and his human shoulder, resulting is said arm ripping loose, and much messiness from all the torn vessels and sinews and such. Not pretty, even if the sound cues were classic.