In: Physics
A string 4.40 m long is held fixed at both ends. If a sharp blow is applied to the string at its center, it takes 0.0400 s for the pulses to travel to the ends of the string and return to the middle.
a)What is the lowest standing wave frequency for this string?
b)What is the second lowest standing wave frequency for this string?
(a)
The lowest standing wave frequency(or fundamental frequency) of the string is given by the expression
The velocity of the sound can be deterimed using the kinematic euqation
Now, the acceleration of the pulse can be found using the equation
Hence, the velocity of the sound on the string is given by
Now, the fundamental frequency of the string is
Therefore, the lowest standing wave frequency of the string is 25 Hz.
(b)The second lowest standing wave frequency for this string is equal to th first harmonic.
Therefore, the second lowest standing wave frequency for this string is 50 Hz.