**Question:**

**The displacement of a string is given by y(x,t) = 0.06 sin (2πx/3) cos (120πt) where x and y are in m and t in s. The length of the string is 1.5 m and its mass is 3.0 × 10-2kg.**

**(a) it represents a progressive wave of frequency 60 Hz**

**(b) it represents a stationary wave of frequency 60 Hz**

**(c) it is the result of the superposition of two waves of wavelength 3 m, frequency 60 Hz each travelling with a speed of 180 m/s in the opposite direction**

**(d) amplitude of this wave is constant**

**Solution:**

The correct answers are

(b) it represents a stationary wave of frequency 60 Hz

(c) it is the result of the superposition of two waves of wavelength 3 m, frequency 60 Hz each travelling with a speed of 180 m/s in the opposite direction