The calculation of the y-component is similar to that of the x. The only difference is that the y-component of vector A is AB instead of OB. So, we will have a \(\sin\) instead of a \(\cos\)

That is, the y-component, which is nothing but the length AB, is

\(\text{AB} = \text{OA} \times \sin 30^{\circ} = 10 \times \sin 30^{\circ}\)