試題詳解

43. One rope is wiggled with frequency f = 2.0 Hz, amplitude A = 1.0 m, and wave speed v = 4.0 m/s. What is the mathematical description of this wave?
(A) y(x,t) = cosπ (2x − t)
(B) y(x,t) = cosπ (2x + t)
(C) y(x,t) = cosπ (x − 2t)
(D) y(x,t) = cosπ (x + 2t)
(E) y(x,t) = cosπ (x − 4t)