Great Christmas Day Dunks from LeBron James!

The NBA does a great job putting games on Christmas Day that showcase the league's biggest stars.  One of yesterday's games had the Los Angeles Lakers hosting the two-time defending champs, the Miami Heat.  LeBron James had a few fantastic dunks during the game.  My favorite were two he got in the first half, both of which were assisted by Dwyane Wade.

With just under four minutes left in the first quarter, Wade drove into the middle of the key and threw the ball up after he was only a couple of feet into the lane.  James was flying in from the left and caught the ball when it was more than five feet from the basket.  The image below shows James just as he caught the ball from Wade (click on the image for a larger view).

James left the court at nearly 10 mph and took about half a second to leave the court, grab the ball, and slam it into to the basket.  He threw the ball into the hole at a speed of about 36 mph.  The ball was rotating at close to 145 rpm with respect to his right shoulder.  That rotational speed is about one third of the rotational speed of helicopter blades.

Moving on to under three minutes left in the first half, James had a dunk that was even more impressive that the one I showed above.  Wade drove down the right side of the key and after going about four feet passed the foul line, tossed the ball up with his right hand.  James was driving into the lane, just slightly left of center.  Wade's toss actually went off the backboard before James caught it, and then followed with a dunk that had his head under the basket as the ball went through the hoop.  The image below shows James just as he is catching the ball from its flight off the backboard (click on the image for a larger view).

As with the first dunk I described, James left the court at nearly 10 mph and was airborne for about half a second before throwing the ball into the hoop.  The ball was moving about 13 mph away from the hoop when he caught it at the instant shown above.  James then reversed the ball's trajectory by accelerating it to about seven times the magnitude of the acceleration due to gravity, or, simply, 7 g's.  He threw ball into the basket at a speed of nearly 23 mph.

Both dunks described here require an extraordinary amount of athleticism.  There may only be a tiny number of people walking the planet who could do what James did.  Those dunks were certainly Christmas treats for those of us watching!

The Brazuca ball is here!

A couple of days ago, Adidas unveiled the ball that will be used in the 2014 World Cup.  Fans voted last year to name the ball Brazuca.  Check out the colorful ball below (click on the image for a larger view).  The image is a cropped version of an image found at Footy-Boots.

For closer views of the ball, check out more images over at Footy-Boots.

As a sports physicist, I am intrigued by the six thermally-bonded textured panels.  Recall that the Jabulani ball used in South Africa for the 2010 World Cup had eight thermally-bonded textured panels.  The 2006 World Cup in Germany employed the Teamgeist ball, which was the first World Cup ball that did not have 32 panels.  The Teamgeist ball had 14 thermally-bonded panels, but those panels were not textured.

As panel number decreases, textures have to be added if the ball is to have aerodynamic properties similar to balls with more panels.  Making balls smoother with fewer panels leads, perhaps counterintuitively, to larger air drag.  Adding textures to the panels roughens the ball's surface and reduces air drag.  The idea is to add enough texturing to the panels to compensate for the fewer seams when panel number is reduced.  No two World Cup balls have the same aerodynamics properties.  It will be interesting to hear what players have to say about the ball after early World Cup matches.  There always seems to be some whingeing.  Just look back at the start of the 2010 World Cup!

There are 189 days before the 2014 World Cup begins.  I can't wait!