A travelling wave is produced on a long horizontal string by vibrating and end up and down sinusoidally. The amplitude of vibration is 10 cm and the displacement becomes zero 200 times per second. The linear mass density of the string is 010 kg m1 and it is kept under a tension of 90 N. (A) Find the speed and the wavelength of the wave. (B) Assume that the wave moves in the position x-direction and at t = 0, the end x = 0 is at its positive extreme position. Write the wave equation. (C) Find the velocity and acceleration of the particle at x = 50 cm at time t = 10 ms.

A. 30 m s1, 30 cm


The speed will be,





As the displacement becomes zero 200 times per second, the frequency will be, f=100 Hz.




B. y = (10 cm) cos 2π


At, t=0, and x=0 it has maxima.


So, it consists a phase of ∏/2.


The equation becomes,




C. 54 m s1, 20 km s2


The velocity of the particle will be,



At x=50cm and t=10ms;



Now, let us calculate the acceleration



At x=50cm and t=10ms;



1