Question 207392
S = -16t^2 + 150t + 5
It's the right formula.  It's usually height as a function of time,
h(t) = -16t^2 + 150t + 5
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When it hits the ground, h = 0
0 = -16t^2 + 150t + 5
-16t^2 + 150t + 5 = 0
*[invoke solve_quadratic_equation -16,150,5]
The solver uses x, just sub that for t.
The negative value is ignored.
t =~ 9.4082 seconds