An object with mass 5 kg is acted upon by a force, `vecF = (-3hati + 4hatj)` N. If its initial velocity at t = 0 is `vecv = (6hati – 12hatj)` m `s^(-1)`, the time at which it will just have a velocity along y-axis is

Options

A. 2 s
B. 5 s
C. 15 s
D. 10 s

Answer

D

Explanation

(d): Initial velocity along x-axis = `(-3)/5` m `s^(2)`
Using `v_(x) = u_(x) + a_(x)t`
Time required for velocity along x-axis to become zero `t = (v_(x)-u_(x))/(a_(x)) = (6-0)/(-3//5) = (30)/3 = 10` s