If an object is dropped from a height of 256 feet, the function h(t)=-16t^+158 gives the height of the object after t seconds. When will the object hit the ground?

Answer 1

h(t) = -16t^2 + 158

0 = ground level = -16t^2 + 158

16t^2 = 158

t^2 = 158/16 =79/8

t = sqr(79/8) = a little over 3 seconds

BUT if initially dropped from 256 feet the equation should have been

h(t) = -16t^2 + 256

Then

0 = -16t^2 +256

t^2 = 256/16 = 16

t = sqr16 = 4 seconds to hit the ground'

Odds are that's the answer you want

Answer 2

256 = -16t² + 158

98 = -16t²

6.126 = -t²

-6.125 = t²

t² cannot be negative. Something is incorrect in your statement of the problem.