Question

A model rocket is shot straight into the air. Its height in meters a "t" seconds is given by h=-4.9^2+29.4t.
a) What is the rocket's initial height?
c)When does the rocket reach the ground?

Answer 1

h = -4.9t^2 + 29.4t

for the initial height, t = 0 , so h = 0

"reach the ground" implies h = 0
-4.9t^2 + 29.4t = 0
t(-4.9t + 29.4) = 0
so t = 0 ----> the initial time and height
or
t = 29.4/4.9 = 6

so it will return to the ground after 6 seconds