If $\vec{a}=5\hat{i}+\hat{j}+3\hat{k}$ then the sum of projections $\vec{a}$ on x axis, y axis and z axis is :

$\frac{9}{\sqrt{35}}$ 9 $\frac{5}{\sqrt{35}}$ 5

9

The correct answer is Option (2) → 9 Sum of projections = proj. (x-axis) + proj. (y-axis) + proj. (z-axis) = 5 + 1 + 3 = 9