The G string on a guitar is a 0.46 mm diameter steel string with a linear density of 1.3 g/m. When the string is properly tuned to 196 Hz, the wave speed on the string is 250 m/s. Tuning is done by turning the tuning screw, which slowly tightens - and stretchs - the string. By how many mm does a 75 cm long G string stretch when it's first tuned?