OT Golf & Physics & how does launch monitor measure swing speed

[dailybuck777]

I have a Swing Caddie 2 launch monitor, which among other things measures swing speed and ball speed. I was using it for my 5 wood and switched to my driver. But forgot to set it for my driver. I got a swing speed of 101 and a ball speed of 139 mph. (Distance for 5 wood was computed at 236 yards -- If driver had been plugged in the distance would have been about 255 to 265) The 101 swing speed was my highest of year. (Have had several 100 mph readings this year) I don't know why 101 swing speed wouldn't have been legitimate, but am checking just in case swing speed may have been inaccurate because I was using a driver and Swing Caddie thought I was using a 5 wood.