The diagrams show the structure of a violin and a close-up of the tuning pegs.
The strings are attached at end X then pass over a bridge which acts as a fixed point. The strings are also fixed at the other end, where they are wound around cylindrical spools, fixed to tuning pegs.
Strings for musical instruments create notes according to their tension and a property of the string called mass per unit length, μ.
The properties of the string and the frequency of the first harmonic are related by the equation:
Where f = frequency of first harmonic (Hz), L = length (m), T = tension (N) and μ = mass per unit length (kg m−1).
The mass of a particular string is 1.4 × 10–4 kg and it has a vibrating length of 0.35 m. When the tension in the string is 25 N, it vibrates with a first-harmonic frequency of 357 Hz.
(a)
When the tension in the string is 50 N
(i)
Calculate the mass per unit length, μ of the string.
[2]
(ii)
Using the equation provided, calculate the speed at which waves travel along the string.
[3]