I guess use a high speed camera Time it and measure the distance travelled.
By Speed Radar !!
A radar gun measures speed of a moving object basically cops use them
A portable radar unit
Radar was first used to measure the speed of a moving object in 1935. By 1938, they were used to measure the speed of a fastball thrown by Bob Feller.
A Radar gun
You can use a radar gun to measure your break speed. On a simpler level, there is a smartphone app called Break Speed, which does just that.
160.43 by shaun tait
Radar is a system that uses radiowaves to measure things like size, distance and speed of a specific object.
you usually are supposed to use a radar gun...
Current technology allows the use of a "radar gun" to determine the speed of a cricket ball. There is a slight problem in that the ball is frequently thrown "down"