A violinist is tuning her instrument to concert A (440 Hz). She plays the note while listening to an electronically generated tone of exactly that frequency and hears a beat of frequency 4.00 Hz, which increases to 5.00 Hz when she tightens her violin string slightly. Part A What was the frequency of her violin when she heard the 4.00 Hz beat? Express your answer to three significant figures and include the appropriate units. ? f = Value Units Part B To get her violin perfectly tuned to concert A, should she tighten or loosen her string from what it was when she heard the 4.00 Hz beat? O She should tighten her string. O She should loosen her string.