a. State two similarities and two differences between progressive waves and stationary waves.

b. This diagram shows an experiment to measure the speed of a sound in a string. The frequency of the vibrator is adjusted until the stationary wave shown is formed.

On a copy of the diagram, mark a node (label it N) and an antinode (label it A). The frequency of the vibrator is 120 Hz. Calculate the speed at which a progressive wave would travel along the string.

c. The experiment is now repeated with the load on the string halved. In order to get a similar stationary wave the frequency has to be decreased to 30 Hz. Explain, in terms of the speed of the wave in the string, why the frequency must be adjusted.

Transcribed Image Text:

vibrator pulley 75 cm slotted masses Figure 14.20