Application of Quadratic Equations

Question

An object is launched with an initial velocity of 96 ft/sec. The height h (in feet) of the object after t seconds is given by h = -16t^2+96t.

A) From what height is the object launched?

B) How high is the object after 3 seconds?

C) When does the object reach a height of 128ft?

D) When does the object hit the ground?

Answer 1

a) h = 0 feet high

b) at t=3, h= 192 feet

c) '-16t^2 +96t -128=0 = -16(t^2 -6t + 8) = 0

(t-8)(t+6) = 0, t = 8 seconds when h = 128 ft

d) it hits the ground in 6 seconds