Guidelines on Velocity
The USGA and The R&A (the European golf governing body) rule that the velocity of the golf ball shall not be greater than 250 ft. (76.2 m.) per second.
Effects on Speed
There are several factors that can affect ball velocity. Club speed is a big contributor; however, hitting the sweet spot of the club is the most important factor. The material of the club and angle of approach can also produce varying ball speeds. Titanium offers the greatest increase to ball velocity.
Calculating Ball Velocity
To capture the velocity of the ball use this equation:
velocity = (clubhead speed x coefficient of restitution) / (1.0 + (mass of ball / mass of clubhead))
1.62 oz. is the weight of most golf balls.
Example of Velocity
With a 100-mph swing, using an 11-degree driver with .825 COR and 200 gram head weight, assuming a center hit the golf ball, velocity would be 148 mph.
Average Pro Speeds
When testing equipment, the USGA uses a swing speed of 109 mph to simulate a professionals swing speed. This results in a ball speed of around 180 mph.
Velocity and Air Resistance and Gravity
The fastest velocity is just after impact. The golf ball will continue to lose speed until it reaches its peak height. The ball will then face a loss of momentum and spin rate due to air resistance and gravity.