SOLUTION: A ball is projected upward from ground level. After t seconds its height in feet is a function defined by f(t)= -16t2 + 48t. After how many seconds will it reach a height of 32 ft?

Question 200691: A ball is projected upward from ground level. After t seconds its height in feet is a function defined by f(t)= -16t2 + 48t. After how many seconds will it reach a height of 32 ft?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A ball is projected upward from ground level.
After t seconds its height in feet is a function defined by f(t)= -16t2 + 48t.
After how many seconds will it reach a height of 32 ft?
:
height h = f(t)
:
equation when height = 32:
-16t^2 + 48t = 32
:
-16t^2 + 48t - 32 = 0; subtract 32 from both sides
:
Simplify, divide by -16 (changes the signs)
-16(t^2 - 48t - 2) = 0
:
factors to:
(t - 2)(t - 1) = 0
;
Two solutions:
t = 1 sec; at 32 ft on the way up
and
t = 2 sec; at 32 ft on the way down
:
:
Given equation looks like this; (t on the x axis, h on the y axis):

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