$3.$ Two hockey pucks of mass $0\mathrm{.}20$ kg collide. Initially, puck $1$ moved at $35$m$/$s to the right and puck $2$ was at rest. After the collision, puck $1$ moves at $20\mathrm{.}0$m$/$s at an angle of $45\backslash$deg from the original direction of motion. What is the velocity of puck $2$ after the collision? $(/2)$