Question

A ball is thrown into the air with an upward velocity of 28 ft/s. Its height (h) in feet after t seconds is given by the function h = –16t² + 28t + 7. How long does it take the ball to reach its maximum height? What is the ball’s maximum height? Round to the nearest hundredth, if necessary.

A.1.75 s; 7 ft
B.0.88 s; 43.75 ft
C.0.88 s; 17.5 ft
D.0.88 s; 19.25 ft
I think it is D....?

Answer 1

h = -16t^2 + 28t + 7
dh/dt= -32t + 28 = 0 for a max of h
32t = 28
t = 28/32 = .875
when t = .875
h = -16(.875)^2 + 28(.875) + 7
= 19.25 ft


looks like D, you are correct

Answer 2

Its D guys don't worry