an object is 420 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.) can someone help me work this out please I dont understand any of it

Question

an object is 420 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.)   can someone help me work this out please I dont understand any of it

anonymous · Answer

w=Cr^-2

anonymous · Answer

w=420(3963)^2
w=420(15705369)
w=6596254980

mertsj · Answer

You did it right.

anonymous · Answer

ok I got that part do you mind if i give you the next step and see if its right?

anonymous · Answer

so is that my c value?

mertsj · Answer

Oh.  Sorry.  I didn't notice that you messed up your variables.
First rewrite the equation so that it says:  w = C/r^2
Now multiply both sides by r^2 so you have:  w(r^2) =C
Then replace w with 420 lbs and r with 3963 miles, square r and multiply by 420 and you will have C.

anonymous · Answer

so will it be 420(3963)^-2=6596254980?

anonymous · Answer

no wait thats the same thing isnt it lol

mertsj · Answer

So it will be (420)(3963)^2 = C
(420)(15705369)=C
6596254980 = C

anonymous · Answer

ok then my next step is to use the value of c to find how much the object would weigh is it is 450ft about sea level

anonymous · Answer

w=6596254980(3963-450/5280)^-2