Question

Heather dropped a water balloon over the side of her school a height of 80 feet. The approximate height of the balloon at any point during it's fall can be represented by the following quadratic equation: h=-16t^2+80. About how long did it take for the balloon to hit the ground.A.1.73B.2.24C.2.45D.2.83

Answer 1

h = - 16t^ 2 + 80

$h=-16t^2\text{ + 80}$

The balloon will hit the ground when the height = 0

$\begin{gathered} 0=-16t^2\text{ + 80} \\ \text{collect like terms} \\ \\ 16t^2\text{ = 80} \\ \text{Divide both sides by 16} \\ t^2\text{ = }\frac{80}{16} \\ t^2\text{ = 5} \\ t\text{ =}\sqrt[]{5} \\ t\text{ = 2.236} \\ t\text{ = 2.24} \end{gathered}$

The correct option is B = 2.24