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Sissy Devane

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My son is very confused about a problem and I failed math 27 years ago.
here is the problem

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). Hint: C is a constant and r is the distance that the object is from the center of the earth.
We know that we are using either one these$ equations but we don’t know what to do next after we substitute the information.
r = ?(c/w) or w = c/( r^2 )

Please someone help, I feel bad that I can't help him.
 
Sissy Devane said:
My son is very confused about a problem and I failed math 27 years ago.
here is the problem

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). Hint: C is a constant and r is the distance that the object is from the center of the earth.
We know that we are using either one these$ equations but we don’t know what to do next after we substitute the information.
r = ?(c/w) or w = c/( r^2 )

Please someone help, I feel bad that I can't help him.
Click to expand...

What answer did he get when he calculated r and w?

Why is your son himself not asking these questions - it will be better if he communicates directly.

DUPLICATE POST:
Answered at:

viewtopic.php?f=9&t=35415&p=137487#p137487
 
Sissy Devane said:
I have r = 3,963 and w 100

3,963 = ?(C/100) <<< Correct - now calculate 'C' from here

Is this correct so far?
Click to expand...
 
Okay, I think that the next step is to remove the radical to do that I square both sides
3,963 = ?(C/100)
?(3,963)?^2 = (?(C/100) )^2
15,705,396 = C/100
I think this is correct, I have no clue as to what to do with this problem, am I correct so far?
 
Sissy Devane said:
Okay, I think that the next step is to remove the radical to do that I square both sides
3,963 = ?(C/100)
?(3,963)?^2 = (?(C/100) )^2
15,705,396 = C/100 <<<< Correct - now calculate C
I think this is correct, I have no clue as to what to do with this problem, am I correct so far?
Click to expand...
 
That's where I get stuck, I assume that I subtract C from both sides or 100 to try and get C alone.
3,963 = ?(C/100)
?(3,963)?^2 = (?(C/100) )^2
15,705,396 = C/100
I will try subtracting 100 which seems more logical to me
15,705,396 – 100 = C
15,705.296 = C
Please say this is correct?
 
Sissy Devane said:
That's where I get stuck, I assume that I subtract C from both sides or 100 to try and get C alone.
3,963 = ?(C/100)
?(3,963)?^2 = (?(C/100) )^2
15,705,396 = C/100
I will try subtracting 100 which seems more logical to me <<< Incorrect

15705396 = C/100

15705390 * 100 = C/100 *100

1570539000 = C *1

1570539000 = C

15,705,396 – 100 = C
15,705.296 = C
Please say this is correct?
Click to expand...
 
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