A transverse harmonic wave on a string is described by `y ( x,t )= 30 sin ( 36 t + 0.018 + ( pi)/(4) ) `where x and y are in cm and t is in s.The positive direction of x is from left to right.
What is the least distance between two successive crests in the wave ?

Explanation

Given, `y ( x,t) = 3.0 sin ( 36 t +0.018 x + ( pi)/(4))`
`kx= 0.018x`
so that `k = ( 2pi)/( lambda ) =0.018` rad `cm^(-1)` i.e., `lambda = (2 xx 3.142)/( 0.018) cm`
`lambda=349.1cm = 3.49 `m.
`lambda = 3.5m`