An astronaut $r$ thousand miles from the center of the earth weighs $2820 / r^2$ pounds. The surface of the earth is 4000 miles from the center.

(a) If the astronaut is $h$ miles above the surface of the earth, express $r$ as a function of $h$. Enter your answer as an equation, such as $r = 5h-1$.
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(b) Express the astronaut's weight $w$, in pounds, as a function of $h$. Enter your answer as an equation, such as $w = 5h-1$.
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