<p>Hi. I have a question on the June 2005 Physics NYS Regents. </p>
<p>A satellite weighs 200 newtons on the surface of Earth. What is its weight at a distance of one Earth radius above the surface of Earth? </p>
<p>Can someone help me with a detailed explaination? Thanks!!</p>
<p>Seems simple enough...</p>
<p>By Newton's law of gravitation (for which I'm sure there's a better name than the one I just used), the force of gravity is GMm/r^2. Here, that quantity is equal to 200 newtons. r = 1 earth radius because Earth's surface is 1 radius away from its center. Plugging in r = 1, makes GMm equal to 200 N. To simulate being 1 earth radius above the surface of the earth, one would make the total distance to the earth's center of mass equal to 1 + 1 = 2 radii. Plug r = 2 into the equation. Now we get F = GMm / (2^2) = GMm/4. Since GMm was equal to 200 N, divide 200 by 4 to get a new gravitational force of 50 N.</p>
<p>A question, what makes this "impossible" and makes it require someone who got a 750+ on the SAT II Physics test? ...Unless I did it completely wrong. You want hard physics questions? Check out cfso1952's "Some Physics Questions" post. Eek.</p>
<p>Thanks! I really appreciate it!</p>