A projectile is thrown upward so that its distance above the ground after t seconds is h = - 16t2 + 608t.

After how many seconds does it reach its maximum height?

Question

A projectile is thrown upward so that its distance above the ground after t seconds is h = - 16t2 + 608t.

After how many seconds does it reach its maximum height?

anonymous · Answer

please help!!

amistre64 · Answer

its maximum is defined at its vertex

amistre64 · Answer

the vertex of $$ax^2+bx+c$$is defined when
$$x=-\frac b{2a}$$

anonymous · Answer

38 s

 19 s

 28.5 s

 9 s

 those are the answer choices.. so woulnt it be 38 s

amistre64 · Answer

38 is how long it takes to hit the ground again

amistre64 · Answer

it would tak half that time to go up, then half of it to come back down again

anonymous · Answer

so then it be 19s???

amistre64 · Answer

yep