. The equation of a vibrating string, fixed at both ends, is given by
where x is the distance (in cm) measured from one end of the string, t is the time (in seconds), and y gives the displacement. The string vibrates in 4 loops.
The speed of transverse waves along the string equals, for the fundamental mode
A. 60 m/s
B. 120 m/s
C. 30 m/s
D. 15 m/s.