When a dark gun is shot upwards, the applicable equations are:
y= v0t sin θ − 1/2 gt2
R = ∆x(t = 2v0 sin θ/g) = v^2 sin(2θ) / g
when t is 4.1 seconds and θ = 90 degrees,
we can see in the horizontal range sin(2θ) or sin 180 is equal to zero. Hence the range is equal to zero
