1. Why does the stroboscope appear to make the vibration stop at certain frequencies? Why does it appear to be two strings at 240 Hz and three strings at 360 Hz?
2. As mass is added to the mass holder an elogation or stretching of the string itself may occur. How does this affect the results of the experiment?
3. If you were to use a string which had 4 times the mass of the string used in the experiment, how much tension would have to be applied in order for it to have a standing wave of 3 1/2 wavelengths long? Use values for other parameters from your data.