Calc
posted by Pat on .
If a ball is thrown vertically upward with a velocity of 160 ft/s, then its height after t seconds is s = 160t  16t2.
What is the velocity of the ball when it is 96 ft above the ground on its way up? (Consider up to be the positive direction. Round the answer to one decimal place.)
What is the velocity of the ball when it is 96 ft above the ground on its way down? (Round the answer to one decimal place.)

*Revised*
If a ball is thrown vertically upward with a velocity of 160 ft/s, then its height after t seconds is s = 160t  16t^2.
What is the velocity of the ball when it is 96 ft above the ground on its way up? (Consider up to be the positive direction. Round the answer to one decimal place.)
What is the velocity of the ball when it is 96 ft above the ground on its way down? (Round the answer to one decimal place.) 
velocity= ds/dt= 16032t
use the s formula to find t (you get two t, a quadratic) when s=96
then put those times in the velocity equation above. 
that is what i am having trouble with =/
i got 96= 160t16t^2 and i don't know how to factor. so i tried 16t^2+160t96 and used the quadratic formula and i got two answer: .6 and 9.4...i do not know what i am doing wrong, but i really need help finding t when it's 96 feet.
Thank you.