SOLUTION: if a model rocket is propelled upward from ground level at an initial velocity of 112 feet per second, after t seconds, its height h is given by the formula h= -16t^2 + 112t. After

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: if a model rocket is propelled upward from ground level at an initial velocity of 112 feet per second, after t seconds, its height h is given by the formula h= -16t^2 + 112t. After      Log On


   



Question 345413: if a model rocket is propelled upward from ground level at an initial velocity of 112 feet per second, after t seconds, its height h is given by the formula h= -16t^2 + 112t. After how many seconds will its height be 192 feet?
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Given:
h= -16t^2 + 112t
.
Set h = 192 and solve for t:
192 = -16t^2 + 112t
0 = -16t^2 + 112t - 192
dividing both sides by -16:
0 = t^2 - 7t + 12
factoring:
0 = (t-3)(t-4)
t = {3, 4}
It will be at 192 feet at 3 and 4 seconds