question in description

Question

if an egg is thrown up and off the roof of a 100 foot building with an initial upward velocity if 100 foot per second, how long until it hits the ground 

Answer 1

h(t) = 100 + 100t - 16t²,

 

with h in ft and t in sec.

 

Set h(t) = 0 and solve for t.

 

-16t² + 100t + 100 = 0

 

Solve this quadratic equation for t.  Do you know how to do that?  You should get a negative solution and a positive solution.  Discard the negative solution, since time starts at t = 0 at the moment of the throw.