The equation of a wave travelling on a string is given by Y(mn) = 8 sin[`(5m^(-1)x-(4s^(-1)t`]. Then
A. velocity of wave is 0.8 m/s
B. the displacement of a particle of the sting at t= 0 and `x = (pi)/(30)` m from the mean position is 4 mn
C. the displacement of th mean position at t = 0, `x = (pi)/(30)`m is 8 m/s
D. velocity of the wave is 8 m/s
