Answer:
2.5 second
Step-by-step explanation:
The equation is missing in the question.
The equation is, [tex]h=-8t^2+40t[/tex] , where 'h' is the height and 't' is time measured in second.
Now we know to reach its maximum height, h in t seconds, the derivative of h with respect to time t is given by :
[tex]\frac{dh}{dt} =0[/tex]
Now the differentiating the equation with respect to time t, we get
[tex]\frac{dh}{dt}=\frac{d}{dt}(-8t^2+40t)[/tex]
[tex]\frac{dh}{dt}=-16t+40[/tex]
For maximum height, [tex]\frac{dh}{dt} =0[/tex]
So, [tex]-16t+40=0[/tex]
[tex]\Rightarrow 16t=40[/tex]
[tex]\Rightarrow t=\frac{40}{16}[/tex]
[tex]\Rightarrrow t = 2.5[/tex]
Therefore, the ball takes 2.5 seconds time to reach the maximum height.