SOLUTION: An emergency flare is launched from platform and its height h in metres after t seconds is given by the equation h =-4.9t^2 + 78.4t + 11.3 a)What is the maximum height of the fl

Question 1051603: An emergency flare is launched from platform and its height h in metres after t seconds is given by the equation h =-4.9t^2 + 78.4t + 11.3
a)What is the maximum height of the flare?
b) after how many seconds does the flare reach the maximum height?
c) when will the flare hit the ground below?
d) determine the height of the platform
My attempt
a) -4.4(x-8)^2+324.9
b) 11.3 seconds
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
h =-4.9t^2 + 78.4t + 11.3
h = -4.9(t-8)^2 + 4.9(64) + 11.3
h = -4.9(t-8)^2 + 313.6 + 11.3
h = -4.9(t-8)^2 + 324.9 Good Work
Parabola opening downward V(8, 324.9)
a) maximum height = 324.9m
b) after how many seconds does the flare reach the maximum height: t = 8sec
c) when will the flare hit the ground below? h = 0
0 =-4.9(t-8)^2 + 324.9
4.9(t-8)^2 = 324.9
(t-8)^2 = 324.9/4.9
t =
d) determine the height of the platform:
h =-4.9t^2 + 78.4t + 11.3
t = 0, the height of the platform is 11.3m
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