The initial velocity of the ball is in horizontal direction.
The initial velocity in vertical direction is zero.
For vertical motion, `u_x = 5 m s^-1, u_y = 0`
Displacement in vertical direction, `y = -h = -20 m`
`-h = (1)/(2) - "gt"^2 rArr (2 xx 20)/(10) = t^2 rArr t = 2 s`
Horizontal displacement : Distance covered in `2 s`,
`x = d = u_x xx t = 5 xx 2 = 10 m`
Since the length of one car is `4 m`, it will hit the third car for which `8 m lt d lt12 m`.