After how many seconds will the ball hit the ground?

Question

A ball is thrown upward at 56 ft per second. An equation that gives the height h of the ball above the ground after t seconds is
h=56t-16t^2.

After how many seconds will the ball hit the ground?

how do you figure it out?

Answer 1

h(t) = 56 t - 16 t ²
0 = 56 t - 16 t²
16 t ² - 56 t = 0
(4 t) (4 t - 14 ) = 0
t = 0 , t = 3.5
Will hit ground after 3.5 sec
Given h(t) , the initial velocity is of no consequence.

Answer 2

3.5, i think..let h=o and equate for t