Mikalee, a fighter pilot, ejects from her burning plane. Once she is safely on the ground, she launches a flare to attract the attention of a rescue plane. The initial velocity of the flare is 1600 ft/sec. The path of the flare is represented by the function h(t) = - 16t^2 + 1600t where t is the time in seconds and h(t) is the height of the flare.

How long does it take the flare to reach the maximum height?

40 sec

4 sec

50 sec

40,000 sec

Question

Mikalee, a fighter pilot, ejects from her burning plane.  Once she is safely on the ground, she launches a flare to attract the attention of a rescue plane.  The initial velocity of the flare is 1600 ft/sec.  The path of the flare is represented by the function h(t) = - 16t^2 + 1600t where t is the time in seconds and h(t) is the height of the flare.

How long does it take the flare to reach the maximum height?

		
40 sec

		
4 sec

		
50 sec

		
40,000 sec

anonymous · Answer

$$ h(t) = - 16t^2 + 1600t$$ max is at $t=-\frac{b}{2a}=-\frac{1600}{2\times 16}$