Agolf ball í hit off the ground at an angel pi/6 travels 400ft. how long in the air

You can write the equations of motion as
   h(t) = -16t² + v₀sin(θ)t
   d(t) = v₀cos(θ)t

Solving the second of these for t and substituting into the first equation gives the time of flight as
   0 = -16t² + d(t)·tan(θ)
   t = √(d(t)·tan(θ)/16)

So, for d(t) = 400 and θ = π/6, this becomes
   t = √((400/16)/√3)
   t = 5/√(√3) ≈ 3.79918

The ball is in the air about 3.80 seconds.