At time t = 0 and at position x = 0 m along a string, a rightward (+x dir) travelling sinusoidal wave with frequency of 220 Hz has displacement y = +4.0 mm and transverse velocity vy = -0.75 m/s.
a) What is the smallest positive phase angle for this wave?
phi+ =
b) What is the amplitude of this wave?
c) How long does an observer at x=0 need to wait before a trough (y=-A) arrives?