RUFUS ALEXANDER
OKLAHOMA LINEBACKER
Two large bodies, moving at fast speeds, collide head-on. If that sounds like a demolition derby, it's because it is. "Newton's Second Law" is how Nebraska prof Dr. Tim Gay, author of The Physics of Football, prefers to see it. "Force equals mass times acceleration." But when Alexander cracks a tailback, our physicists say it's similar to the force generated by one car ramming another's grill at 40 mph, except instead of the target being belted safely in a vehicle, he is buried under 231 pounds of muscle. Alexander, who racked up 102 tackles and 17 TFLs as a junior last year, says the key to surviving the impact—on his end, anyway—is never hesitating. "If you do, you absorb all the contact," he says. "So I keep my feet moving. And I never shy away. I get a thrill out of the contact." Steer clear.
FRANK OKAM
TEXAS DEFENSIVE TACKLE
When Okam (6'5", 315) smashes into a center, neither has had much space to build up steam. But don't let the cramped quarters lull you. Our physicists say the junior nicknamed Nightmare unleashes a force similar to a major league hitter's best two-by-four swing—70 times a game. But it's not the hit so much as how it's delivered. "It's about who has better leverage," says Todd Leif, who uses football to teach physics at Cloud County CC in Concordia, Kan. Okam knows the advantage of being first off the ball. "On the snap I explode," he says. "I try to stun the guy and knock him over." With 70 career tackles and 11 TFLs, Okam has had his share of knockdowns. "It's not possible to get a big hit every time," he says. "But if I get you, I'm gonna get you pretty good." And not many guys have the stomach for it if he does.
BRANDON MERIWEATHER
MIAMI SAFETY
A tight end crosses into the secondary, but when the ball arrives something else does too: a six-foot, 195-pound missile named Meriweather. And when it does, it is with a force that roughly mimics that produced by a belly flop from a 40-foot-high diving board. That's appropriate, because victims often let out the same noise as a dazed belly flopper. "If it's a real good hit, they go, 'Uhhh!'" Meriweather says. The senior caused more than his share of uhhhs last year, with a team-best 115 tackles and 13 TFLs. In his career, he's racked up 202 tackles and jarred loose four fumbles. On the rare occasion he takes worse than he gives … well, that guy better put his head on a swivel. "It makes me angry," Meriweather says. "And one equally hard hit won't do it. I want to keep getting back at them." Everybody out of the pool!
IA FALO
BOISE STATE GUNNER
No other turf collision can match that of a gunner crashing full-bore into a punt returner. Even little guys pack a wallop. Although Falo stands just 5'7" and weighs 167 pounds, our physicists say he generates about the same power as a snowboarder bursting through a hard-packed snowman at 40 mph. "It feels like I'm gliding," he says. If the return man is lucky, he sidesteps Falo. "The tiniest position change lessens the force," says Breinig. But Falo, a junior, almost always makes the most of his impacts: After last season, he was named the Broncos' most inspirational player and finally bagged a scholarship. "When a guy has just caught the ball, his arms are up and he doesn't see me," Falo says. "I can run right through him." Then he owns his foe. "You put a scare into him," he says. "That's what you like to see." Unlike snowflakes, all beat-down returners look alike.