Question

the force of attraction between two magnets is inversely proportional to the square of the distance between them. when the magnets are r cm apart, the force of the attraction between is F newtons (N). if the distance between the magnets is increased by 400%, the force of magnets between them becomes cF N . Find the value of c.​

Answer 1

The force of attraction between 2 magnets is inversely proportional to it's distance squared.

That means

`f = \frac{1}{ {r}^(2) }`

so when the magnets are 4 times apart the resultant force is divided 8 times.

So,

`(f)/(8) = (1)/(8) f`

We can see here C=1/8.