## 01 March 2012

### Henri Lansbury's Amazing Cross-Cum Goal!

While I was celebrating Clint Dempsey's goal that gave the US its first-ever win against Italy, I noticed an even more impressive goal.  Playing for England's Under-21s, Henri Lansbury hit a spectacular cross-cum-shot from the left wing that curled into the upper-right portion of the goal while the Belgium goalkeeper Koen Casteels was futilely leaping after it.  YouTube video of the goal may be seen here.  I absolutely had to model that kick!

Lansbury's phenomenal goal took place in Riverside Stadium, which is located in Middlesbrough, England.  The pitch in that football stadium measures 115 yards by 75 yards (105 m by 69 m).  I estimate that Lansbury took the shot from nearly 28 yards (26 m) from the goal line and almost 30 yards (27 m) left of the center of the pitch.  His shot traveled approximately 40 yards (37 m) to the goal.  After I timed the shot several times, I estimate a time of flight of 2 s.

Incorporating drag and Magnus forces on the football, I determined the launch parameters needed to get the football into the upper-right portion of the goal.  The graph below shows the three-dimensional trajectory from my model of Lansbury's shot (click on the image for a larger view of the graph).

The red curve shows Lansbury's shot.  My calculated launch speed is 59.8 mph (26.8 m/s).  The blue curve in the above graph shows what the trajectory would have looked like had the football not been spinning, meaning no Magnus force.  Reaching essentially the same height, the ending point of the blue curve is about 9.7 yards (8.9 m) away from the ending point of the red curve and well to the right of the goal.  Lansbury clearly needed spin on the football to make the highlight reel!