Answer:
t=8.81s and t=0.62s
Step-by-step explanation:
Asking for H=88ft and putting units leaves us with the formula:
[tex]88ft=(151ft/s)t-(16ft/s^2)t^2[/tex]
Which can be also written as:
[tex](16ft/s^2)t^2-(151ft/s)t+88ft=0[/tex]
We want t, and this is a quadratic formula of the form [tex]at^2+bt+c=0[/tex], which we know has the solutions:
[tex]t=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]
So we put the relevant values (a=16ft/s^2, b=-151ft/s, c=88ft) on that equation we get:
[tex]t=\frac{(151ft/s)\pm\sqrt{(-151ft/s)^2-4(14ft/s^2)(88ft)}}{2(16ft/s2)}[/tex]
Which for the plus sign gives t=8.81345408729s and for the minus sign gives t=0.6240459127s, which rounding to the nearest hundredth are t=8.81s and t=0.62s
