Question

A projectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = - 16t2 + 640t. After how many seconds does the projectile take to reach its maximum height? Show your work for full credit.

Answer 1

No calculus:
h(t)=-16(t^2-40t)
=-16(t-20)^2+6400
So maximum (vertex) occurs at t=20.

With calculus:
h'(t)=-32t+640=0
Solve for t=20

Answer 2

Awesome! Thank you :)

Answer 3

You're welcome! :)