As I said in my first blog post, I love playing soccer in my free time, so I thought I would finally explore some of the physics behind a really cool technique in soccer of bending the ball. Players often use this skill when taking free kicks to put a spin on the ball and curve their shot into the goal. This technique is famously used my David Beckham and the video below highlights one of the most famous moments when he used this technique to win a match in the World Cup.
It's incredible to see the curved path that the ball takes when you look at the footage of the goal head on. Players like Beckham are able to accomplish this by imparting a spin to the ball. When you kick a soccer ball with the inside of your foot and you hit the ball in its center of gravity, it is going to move off in a straight line. However, if you kick the ball with the front of your foot and kick it slightly off-center and with your ankle bent into an "L" shape, the ball will curve in flight. This is because the applied force on the ball acts as a torque which gives the ball a spin. This spinning in the air then causes the ball to be laterally deflected in flight in what is known as the Magnus effect which causes the "bending" motion of the ball in the air. You can see this represented in the image below:
As you can see its pretty neat to learn about the physics behind this cool soccer technique and learn something new about the game!