Question

The displacement y of a wave travelling in
x-direction is given by
y=10^-3 sin (8001 – 2x + π/3)where x is
expressed in meters and t in seconds. The
speed of the wave motion (in m/s) is
(a) 400
(b) 800
(c) 1200
(d) 200
How?????????????
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Answer 1

V=w/k

v=800/-2=-400

speed is scalar so speed=400(a,,)

Answer 2

v=w/k

v=800/200=400

speed of the wave motion is 400.