Question 194070
Miranda throws a set of keys to her brother who is standing on a third-story balcony with his hands 38 feet above the ground. If Miranda throws the key with an initial velocity of 40 feet per second, the equation h = -16t+40t+5 gives the heigh h of the keys after t seconds. 
1. How long does it take the keys to reach their highest point?
h(t) = -16t+40t+5
The max occurs when x = -b/2a = -40/(2*-16) = 1.25 seconds
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2. How high do the keys reach?
h(1.25) = -16(1.25)^2 + 40(1.25) + 5
h(1.25) = 30 feet
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3. Will her brother be able to catch the keys? Explain.
No, the keys don't reach a height of 38 feet.
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Cheers,
Stan H.