A ball is thrown from a height of 156 feet with an initial downward velocity of 8 ft/s . The ball's height h (in feet) after t seconds is given by the following.

Question

h=156-8t-16t²

Answer 1

What is the question?

Typically they want to know the max height and what time during flight the max height is reached...

AND/OR how long it takes to hit the ground.

156 - 8t - 16t^2 = 0

16t^2 + 8t - 156 = 0

4t^2 + 2t - 39 = 0

t = (-2 +or- sqrt( 4 + 4*4*39))/8

t = 2.8824910215354169..... is how long it takes to hit the ground.

Max occurs at -b/(2a) = 8/32 = 1/4

156 - 8(1/4) - 16(1/4)^2 =

156 - 2 - 1 = 153

Max height of 153 feet occurs at t=1/4 second