AP EAMCET Engineering 2018 Apr 23 Shift 2 Paper

Initial velocity is calculated as,
vi=u‌cos‌θ‌

^

i

+u‌sin‌θ‌

^

j

vi=10√3‌cos‌60°‌

^

i

+10√3‌sin‌60°‌

^

j

vi=5√3

^

i

+15

^

j

Final velocity is calculated as,
vf=u‌cos‌θ‌

^

i

+(u‌sin‌θ−gt)

^

j

vf=5√3

^

i

−5

^

j

The dot product of both velocities is,
vi.vf=25×3−15×5
vi.vf=0
The dot product is zero, so both the velocities are perpendicular to each other.
vi⊥vf