Answer:
t = 5 seconds h = 128 feet
Step-by-step explanation:
The given equation of the object is :
[tex]h(t)=-16t^2+64t+80[/tex] .....1
When it hits the ground,
h(t) = 0
So,
[tex]-16t^2+64t+80=0\\\\t=-1\ s\ and\ t=5\ s[/tex]
The object will hit the ground in 5 seconds.
Now, put t = 1 s in equation (1).
[tex]h(1)=-16(1)^2+64(1)+80\\\\h(t)=128\ ft[/tex]
The object is at a height of 128 ft at 1 second.
