Correct Answer - B
Given mass `= m= 5kg`
Acting force ` =F =(-3hati + 4hatj) N`
Initial velocity at
`t =0, u =(6hati -12hatj)m//s`
Retardation `a =(F)/(m) =(-(3hati)/(5) +(4hatj)/(5))m//s^(2)`
As final velocity is along Y-axis only itsx component must be zero.
From `v =u +at` for `X-`componet only
`0 =6hati - (3hati)/(5)t`
`t =(5 xx 6)/(3) =10s`