Science On! The theory of pitch shots.

Pitch = spin, momentum, launch

Golfer Pitching

What is the secret to a great pitch shot?  A shot that hits close and sticks is all in the physics.

First, the trajectory.  Think about trying to throw a ball at a target.  The only way to be sure of hitting the target with assurity is to throw the ball within the straightest line possible.  Same goes for a pitch shot. (See why it’s called a pitch?) A controlled shot needs to head straight to the target for optimal precision and accuracy.  A high shot spends too much time in the air, which reduces the probability that it will land at the target.

Launched at the ideal trajectory the shot then has to land, which is when the fun begins.  Since there is no one to catch the ball at the other end, we need to stop it in another way.  A low trajectory that is accurate and precise keeps a lot of its forward momentum, unfortunately.  Some forward momentum is lost in compressing the ground at impact, but not much initially, especially with hard, fast greens.  That is why backspin on the golf ball is so important. More backspin equals more stopping power. A spinning ball will hop up, or check, on its initial bounce, and that is when the reverse rotational momentum starts to overcome the forward linear momentum.  The second bounce scrubs off more forward momentum, and with enough backspin, it will stop traveling forward completely. Depending on the ground conditions, it might need another bounce to fully arrest its forward momentum, but with enough backspin, the second hop can kill it dead.  Even more backspin put on the ball then gives golfers the best thrill in the game: a pitch shot that backs up.

How do you create these ideal conditions in a pitch shot?  The answer is traction. A golf swing is ideally sending the clubhead forward at a downward angle of attack just prior to ball strike.  The downward angle catches and compresses the ball into the ground. The grooves on the clubface grip the ball, creating a longer interaction time, and prevent sliding of the ball up the face.  Grooves also help transfer the forward momentum of the swing to lower the initial launch trajectory. Remember, a lower launch angle is more accurate and precise, and better able to hit the target.  The grooves also begin to impart backspin to the ball by grabbing the cover as it starts to roll and move forward. The other big backspin generator is from compressing the ball against the ground from a steeper swing angle.  The optimal swing parameters then send the ball forward on a low, penetrating path with enough backspin to kill all the forward momentum imparted from the swing speed in just a couple hops.

Sounds easy when you break down the science, right?  Of course, it takes a lot of practice to control the club to get the right velocity for the specific shot distance, but the backspin and launch inputs are easy when you pick up a StingRay.