Question 926001
s=vt+16t2
object released from 684 feet the initial velocity is 18 ft/s and air resistance is neglected how many seconds will the object hit the ground?
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Use s(t) = -16t^2 + vt + so
If the in+tial velocity is downward (you didn't say) it's -18.  If it's upward, it's +18.
I'll assume downward.
so is the starting height.
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s(t) = -16t^2 - 18t + 684 = 0
Solve for t
*[invoke solve_quadratic_equation -16,-18,684]
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Ignore the negative solution.
t = 6 seconds