Question

The equation of a wave travelling on a string is y = 4 sin $\frac{\pi}{2}\left( 8t - \frac{x}{8} \right)$if x and y are in cm, then velocity of wave is

• A. 64 cm/sec in – x direction
• B. 32 cm/sec in – x direction
• C. 32 cm/sec in +x direction
• D. 64 cm/sec in +x direction

Answer 1

Answer: (D)

64 cm/sec in +x direction

Answer 2

y = 4 sin $\left( 4\pi t - \frac{\pi}{16}.x \right)$

$\omega = 4\pi,k = \pi/16$

$v = \frac{\omega}{k} = \frac{4\pi}{\pi/16} = 64cm/\sec$ in + x direction.