Physics - Vectors Question with Solution | TestHub

$\vec{P}=P\sin \theta \hat{i}-P\cos \theta \hat{j}$ also, $\vec{Q}=Q\cos \theta \hat{i}+Q\sin \theta \hat{j}$ $\therefore \vec{P}.\vec{Q}=(P\sin \theta \hat{i}-P\cos \theta \hat{j})\cdot (Q\cos \theta \hat{i}+Qsin\theta \hat{j})$ $=PQ\sin \theta \cos \theta -P\cos \theta -Q\sin \theta$ $=0$