Momentum

Imagine yourself in the driver's seat. The windows are down, and the breeze is warm. Your tunes are blasting, you've got the pedal to the metal, and you're feeling like a million bucks. This is gonna be the best road trip ever!

Slight problem: Your destination is east, but you're headed west. Simple solution: Take your foot off the accelerator and jam it on the brake, then turn the steering wheel and change direction. Voilà!

But it doesn't take a rocket scientist to figure out that changing d...