SOLUTION: Inverse Variation: The force of attraction (F) between two opposite electrical charges varies inversely as the square of the distance between them. If F=18 when d=10, find F whe

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Question 1104869: Inverse Variation:
The force of attraction (F) between two opposite electrical charges varies inversely as the square of the distance between them. If F=18 when d=10, find F when d=15.
Thanks in advance. :)
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
inverse variation formula is y = k/x.

let F = y and let d^2 = x and you get F = k/d^2

F = 18 when d = 10, therefore the equation becomes 18 = k/100.

solve for k to get k = 100*18 = 1800.

k is the constant of variation, so k will always remain at 1800 in this equation.

you want to find F when d = 15.

formula becomes F = 1800 / 15^2.

solve for F to get F = 8.