A bar moves along a path without rotating as shown. The position of point $B$ can be described by the equation $r_B=(5+3\mathrm{.}1t)i+(4\mathrm{.}7t+0\mathrm{.}8t^2)j,$ where the coordinates are in meters and $t$ is in seconds. The dimensions of the bar are $L_1=0\mathrm{.}7m$ and $L_2=2\mathrm{.}8m,$ and the angle $=50$

What is the $y-$Component of the velocity of point $C$ at $t=3s$