V = 25 (slider from 0 to 50, step 1)
a = 54 (slider from 0 to 90, step 1)
h(x) = sin(a 3.141592653589793 / 180) x / cos(a 3.141592653589793 / 180) - 5 x^(2) / (cos(a 3.141592653589793 / 180)^(2) V^(2))
dmax: cos(a 3.141592653589793 / 180) sin(a 3.141592653589793 / 180) V^(2) / 5
h1 = If(x > 0, If[x < dmax, h(x)])
tvol: dmax / (cos(a 3.141592653589793 / 180) V)