A transverse sinusoidal wave on a string has a period of $38\mathrm{.}7$ ms and travels in the negative x direction with a speed of $18\mathrm{.}9$ m$/$s$.$ At t $=0,$ a particle on the string at x $=0$ has a displacement of $1\mathrm{.}57$ cm with a transverse speed of $1\mathrm{.}78$ m$/$s$.$ What is the amplitude of the wave? Answer in units of m$.$ Question $6,$ chap $116,$ sect $12.$ part $2$ of $410$ points What is the initial phase angle? Answer in units of $.$