Respuesta :
Step-by-step explanation:
Arthur drops a ball from a height of 81 feet above the ground. Its height as a function of time is given by :
[tex]h(t)=-16t^2+81[/tex]...........(1)
Where
t is in seconds
We need to find the time interval when the height of the ball is less than 17 feets. Equation (1) becomes :
[tex]-16t^2+81<17[/tex]
[tex]-16t^2<17-81[/tex]
[tex]-16t^2<-64[/tex]
[tex]t^2>4[/tex]
[tex]t>2[/tex]
When the time is more than 2 seconds, the height of the ball is less than 17 feet. Hence, this is the required solution.