SOLUTION: I have a story problem that consists of 2 parts. I can't even begin to figure out the first part so I definately cannot figure out the second. I was hoping there would be someone

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Question 175299: I have a story problem that consists of 2 parts. I can't even begin to figure out the first part so I definately cannot figure out the second. I was hoping there would be someone to help me out. Here is the problem:
The weight of an object follows this equation: w=Cr<-2> (the negative 2 is an exponent) where C is a constant, and the r is the distance that the object is from the center of the earth.
1. Solve the equation w=Cr<-2> for r.
2. Suppose that an object is 100 pounds when it is at sea level. Find the value of C that makes the equation true. (Sea level is 3,963 miles from the center of the earth)
Please help.
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
(1)
w=Cr%5E%28-2%29 or
w=C%2Fr%5E2 multiply each side by r%5E2
wr%5E2=C divide each side by w
r%5E2=C%2Fw take the square root of each side
r=sqrt%28C%2Fw%29

(2)
3963=sqrt%28C%2F100%29 or
3963=%28sqrt%28C%29%29%2F10 multiply each side by 10
39630=sqrt%28C%29 take square root of each side
C=199.07

Does this help??----ptaylor