For many people, one of the key attributes that makes golf appealing is its reputation as a thinking person’s game. On a basic level, that includes planning your way around a tough course layout. On a deeper level, the principles of physics can be seen in every facet of the game. By learning about the science of golf, you can hone your game based on a whole new set of data. Today, you’ll learn a bit about the physics that affect golf ball flight, with some help from Newton’s Laws of Motion.
Swing Speed and Ball Mass
Newton’s Second Law states that the relation of an object’s mass, acceleration and force can be understood using the equation Force=Mass(Acceleration). Put simply, the force transferred from the club face to the golf ball influences ball flight, trajectory, and distance. To visualize this effect, consider the many ways in which you swing a given club in order to create different types of shots. There are many other factors that influence ball flight, but F=ma is a good place to start.
Face Angle and Spin
Spin is generated by the face angle and grooves of the club face. It’s important to ball flight because it helps counteract gravity to keep your ball in the air. In this instance, Newton’s Third Law – each action has an equal, opposite reaction – is the key. When a golf ball has backspin, it influences the air around it, causing the air to move faster above the ball, and slower below it. This action causes the ball to press down on the air around it, to which the air reacts equally by pushing the ball higher into the air. Clubs like the sand wedge that generate a lot of spin tend to result in higher ball flight – or a more pronounced parabolic arc – but less distance, compared to a long iron.
Friction and Drag
After your club-face makes contact with golf ball, the results are largely out of your hands. Of course, that doesn’t mean that the ball has stopped being influenced by physical forces. As any golfer who’s played on a windy day can tell you, friction and drag are tough customers. Newton’s First Law, that an object in motion will remain in motion unless acted upon by external force, applies here. The external force, in this case, is wind, and it’s what slows your ball down as gravity brings it back to the ground. Just as the spin of the ball influences the air around it, the air can also influence spin. This is why even a light breeze can turn a small hook or slice into a big one, as it makes sideways spin more pronounced. It is also why golf balls have dimples, which help counteract friction.
When you add up the influences of swing speed, ball mass, face angle, spin, friction, and drag, you can begin to see the many influences acting upon ball flight. So, how can this information help your game? First, it will help you, or a club fitter at a pro shop, select the golf ball and clubs that are best suited to your swing, based on hard data. On the tee, most golfers at least try to estimate the drag and friction effects of wind on their ball, even if they don’t necessarily think about it in those terms. Better understanding friction and drag, though, adds heightened importance, and a useful, extra data point, when planning the perfect shot. In the end, any little thing that can shave a stroke or two is worth considering, right?
Katie Morris is a freelance writer with experience writing in the science, sports and recreation fields.
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