Answer
The y-component of the velocity vector is $6.32\,\mathrm{m/s}$.
Work Step by Step
Magnitude of the velocity vector is given as -
$|v|=\sqrt{v_x^2+v_y^2}$.
Given the magnitude and x-component, the y-component will be -
$v_y=\sqrt{|v|^2-v_x^2}$
or, $v_y=\sqrt{49-9}=6.32\,\mathrm{m/s}$
