A particle `P` is initially at a distance `c'=16m` from a fixed point `O`. The particle `P` moves with a velocity `vecv=5overset(^^)(PO)+3hati`. Where `overset(^^)(PO)` is a unit vector from `P` to `O` at any time `t`. Initially `overset(^^)(PO)` is perpendicular to `hati`. Find the time in seconds after which point `P` meets point `O`.