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needingtoknow
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Homework Statement
Assuming the person weighs 980 N on the surface of the Earth, how would you use ratios to obtain the weight of a person at 128 000 km above the surface of the Earth.
Homework Equations
Fg is proportional to 1/d2
The Attempt at a Solution
The answer in the key says 0.072 N. I didn't know exactly where to start but by working backwards from the answer I have determined that it is 20 times the distance from the centre of Earth. I know how to solve these questions using ratios if I am given the times the distance from the centre of Earth.
For example for a previous question: Three times the distance from the centre of Earth, here is how I solve it.
Fg is proportional to 1/d^2
1x3 = 3 therefore 980 = 1/3^2
980 / 9 = 109 N
This method works everytime when I am given the times the distance from the centre of Earth. But when I am given a specific distance I do not know how to get the answer. Can someone please help? Thanks!