SOLUTION: 5) Crossing a wooden bridge at Letchworth Park, Melissa drops a penny into the water below for good luck. If the height of the penny is modeled by the function h(t)=64

SOLUTION: 5) Crossing a wooden bridge at Letchworth Park, Melissa drops a penny into the water below for good luck. If the height of the penny is modeled by the function h(t)=64 - 16t^2, whe

Question 174663This question is from textbook Amsco's Preparing for the Regents Examination Mathematics B
: 5) Crossing a wooden bridge at Letchworth Park, Melissa drops a penny into the water below for good luck. If the height of the penny is modeled by the function h(t)=64 - 16t^2, where t represents time in seconds and h(t) is height in feet, how many seconds did it take the penny to hit the water?
(a) 1 (b) 2 (c) 3 (d) 4
Show work thank you ! This question is from textbook Amsco's Preparing for the Regents Examination Mathematics B

Answer by nycsub_teacher(90) (Show Source): You can put this solution on YOUR website!
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Here is one of your questions:

5) Crossing a wooden bridge at Letchworth Park, Melissa drops a penny into the water below for good luck. If the height of the penny is modeled by the function h(t)=64 - 16t^2, where t represents time in seconds and h(t) is height in feet, how many seconds did it take the penny to hit the water?
(a) 1 (b) 2 (c) 3 (d) 4

Let h(t) = 0

0 = 64 - 16t^2

Subtract 64 from both sides.

-64 = -16t^2

Now divide both sides by -16.

-64/-16 = t^2

64/16 = t^2

4 = t^2

Finally take the square root of both sides of the equation.

sqrt{4} = sqrt{t^2}

2 = t

The answer is choice (b).

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