Question 390072
 y=-16t^2+38.4t+.96
set y to 0 and solve for t:
 0=-16t^2+38.4t+.96
applying the quadratic equation:
t = {-0.02, 2.42}
throw out the negative solution, leaving:
t = 2.42 seconds
.
*[invoke quadratic "t", -16, 38.4, .96 ]