(a) The wave is travelling to the right (positive x diretion) because of the negative sign in the argument.

(b) Amplitude = 4 m.
Period = 1/f = 2p/w = 2p/3p = 2/3 s.
Wavelength = 2p/k = 2p/6p = 1/3 m
Wave vector = 6p m^(-1)
Freqnecy = 1/period = 3/2 = 1.5 Hz
Angular frequency = w = 3p rad/s

(c) At t = 0.900 s, y = 4sin(2.7p - 6px)
The graph crosses zero when 2.7p - 6px = 0, or +/- p

0; x = 2.7/6 = .45
p; x = 1.7/6 = .28
-p; x = 3.7/6 = .68
2p; x = 0.7/6 = .1
When x = 0, y = 4sin(2.7p) = 3.23


(d) When x = 0.400 m, y = 4sin(3pt - 2.4p)
The graph crosses zero when 3pt - 2.4px = 0, +/- p, +/- 2p, etc.

0; t = 2.4/3 = .8 s
p; t = 3.4/3 = 1.13 s
-p; t = 1.4/3 = .47 s
-2p; t = 0.4/3 = .133 s
-3p; t = -0.6/3 = -0.2 s
When t = 0, y = 4sin(-2.4p) = -3.80


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