Answer to Question #122627 in Optics for Naineshwari

Question

find wave velocity when in shm when y=0.25cos (125t- 0.25x)

Answer 1

We are assuming all the quantities are in S.I.

Wave equation is

$$y=0.25\cos(125t-0.25x)=0.25\sin(0.25x-125t+\pi)$$

Now,

$$k=0.25\implies \lambda=\frac{2\pi}{0.25}=8\pi$$

And,

$$\frac{2\pi v_w}{\lambda}=125\implies v_w=125\cdot4=500m/s$$