Respuesta :
The one which one will be hitting ground first will be projectile launched at angle 30°.
Explanation:
A projectile fired will be having two velocities horizontal velocity and vertical velocity.
If u is the velocity of firing
       Horizontal velocity = u cosθ
       Vertical velocity = u sinθ
Consider vertical motion of projectile, we have equation of motion
        v = u + at
   At maximum height
         Final velocity, v = 0 m/s
         Acceleration, a = -g = -9.81 m/s²
        Initial velocity, u = u sinθ
        0 = u sinθ - 9.81 x t
        [tex]t=\frac{usin\theta }{9.81}[/tex]
        Time of flight of projectile = 2 x t
         [tex]\texttt{Time of flight of projectile =}2\times \frac{usin\theta }{9.81}[/tex]
Here for both projectiles initial velocity is same, time depends upon angle of projection.
           sin 30 = 0.5
           sin 60 = 0.866
So, maximum time is for the projectile which is projected at 60 degrees.
The one which one will be hitting ground first will be projectile launched at angle 30°.
