Question

Write a general formula to describe the variation. F varies inversely with d^2; f=21 when d=7

Answer 1

Given:

F varies inversely with d²

So,

`\begin{gathered} F\propto(1)/(d^2) \\ \\ F=(k)/(d^2) \end{gathered}`

Where (k) is the proportionality constant

We will find the value of (k) using the given condition

When F=21, d= 7

Substitute with (F) and (d):

`\begin{gathered} 21=(k)/(7^2) \\ k=21\cdot7^2=21\cdot49=1029 \end{gathered}`

So, the answer will be:

The general formula to describe the variation is:

`F=(1029)/(d^2)`