(a)[2]
Find an expression for $F$ as a function of $d$.
(b)[1]
If the separation between the two magnets is doubled, the new force becomes $n$ times the original force. Work out the value of $n$.
Mathematics 0580 · IGCSE · Proportion
Proportion — practice question
Between two magnets, the attractive force $F$ Newtons varies inversely with the square of the distance $d$, cm, separating the magnets. If $d = 1.5$, then $F = 48$.