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\textbf{Math 220 (section AD?) \hfill Quiz 6 \hfill Spring 2016} \\
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\textbf{Name}\ \rule{4in}{0.4pt} \hfill
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$\bullet$ You have 15 minutes \hfill $\bullet$ No calculators \hfill $\bullet$ Show sufficient work
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\item (3 points) A bullet is shot upward from the surface of a planet so that its height in meters until coming to rest is given by the equation $s(t) = 210t - 3.5t^{2}$ where $t$ is measured in seconds. Answer the following questions and be sure to use proper units in each answer.\\[0.5in]
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\item What is the acceleration due to gravity on this planet?
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\item What is the bullet's initial velocity?
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\item How long does it take for the bullet to reach its maximum height?
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\item (4 points) A ladder $10$ feet long rests against a vertical wall. If the bottom of the ladder slides away from the wall at a rate of $1.5$ feet per second, how quickly in radians per second is the angle between the ladder and the wall increasing when the bottom of the ladder is $8$ feet from the wall?
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\item (3 points) Suppose that $A$ represents the number of grams of a radioactive substance at time $t$ seconds. Given that $\D{\frac{dA}{dt} = -0.2A}$, how long does it take $18$ grams of this substance to be reduced to $6$ grams?
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