The wave function of a sinusoidal

$7$ points

wave generated on a string is given by: $y(x,t)=0\mathrm{.}1sin(x-5t+),$ where $x$ and $y$ are in meters and $t$ is in seconds. At $t=0,$ an element of the string at $x=0$ has a vertical displacement of $0\mathrm{.}05\sqrt[\phantom{2}]{?}3m$ and is moving down. The phase constant is: