Airplanes `A` and `B` are flying with constant velocity in the same vertical plane at angles `30^(@)` and `60^(@)` with respect to the horizontal respectively as shown in figure . The speed of `A` is `100sqrt(3) m//s` . At time `t = 0 s`, an observer in `A` finds `B` at a distance of `500 m`. The observer sees `B` moving with a constant velocity perpendicular to the line of motion of `A` . If at `t = t_(0)`, A just escapes being hit by `B ,t_(0)` , A just escapes being hit by `B , t_(0)` in seconds is

Options

A. (a) ` 3,5 S`
B. (B) ` 5 S`
C. (C ) ` 6.5 S`
D. (D)` 196. 0 M`

Answer

D

Explanation

Refer to Fig, 2 (CP). 46.
.
` v_1 =v_2 cos 30^@`
or` v_2 = 200 m//s`
:. ` t_0 = d/ (v_2 sin 30^@) = ( 500)/(200 xx 1/2) = 5 s`.