# The Science of the Slam

Dec 27, 2006

Ever wonder why NBA slam masters like Vince Carter or Amare Stoudemire hang in the air so long when they dunk the ball? Is it the shoes? Do they have invisible wings? Kidzworld looks at the science behind the slam dunk.

## Slam Dunks - We Have Lift Off

Believe it or not, Vince Carter, Kobe Bryant and all other NBA players aren't breaking any laws of science when they hang in the air and lay down a reverse tomahawk jam. It just seems like they are. They're actually governed by the same laws of physics as you and everyone else. How high a player jumps depends on how much force he uses to push off the floor when he jumps. The harder he pushes, the higher he goes, and the longer he stays in the air. In other words, Vince Carter gets so much air because he has such a powerful push-off when he goes up for a slam.

## Slam Dunks - Holy Hang Time

A jump of four feet leads to a hang time of one second. That's an unusually high jump and as it turns out, most basketball players, including Vince Carter, don't jump that high. A three-foot-high jump has a hang time of 0.87 seconds. That means all the reverses, twists and turns of the slam dunks, like you see in the NBA Slam Dunk Contest, take place in just eight or nine-tenths of a second!

## Slam Dunks - Do They Actually Fly?

So why does it seem like NBA players are in the air for much longer than one second? Doesn't it seem like Kobe has enough time to make himself a sandwich while he's up above the rim? According to Newton's law, when a player jumps and takes off from the floor toward the basket, the player will come down at the same rate as they rose into the air, as long there is no contact with anything. Vince, Kobe and other high-flying NBA stars make it seem longer because they hold onto the ball longer than other players before dunking, waiting until they're on the way down from their jump to dunk the ball. Players also create an illusion that they are floating or flying by pulling they're legs up and extending their arms as the jump progresses. This makes it seem like they're higher than they really are.

#### Slam Dunks - Moon Jumping

Imagine if Vince Carter ever played b-ball on the moon! Since an object on the moon weighs one-sixth of what it does on earth, Vince Carter would be able to rise six times higher and remain in flight six times longer than on earth. That means Carter would weigh 37 pounds on the moon, would perform vertical leaps of 24 feet and hang in the air for nearly six seconds. That's like jumping over a small two-story building in a single jump!

Related Articles