Question

The force F between 2 objects is inversely proportional to the square of the distance, d between them. The force is 0.36 newtons when the distance between them is 6 metres. Work out the force (2dp) when d = 4.2 metres

I got 0.74 newtons but I was wrong... what would be the answer?

Answer 1

0.73 N to 2 dp.

Explanation:

F = k/d^2 where k is a constant , F = force and d = distance.

Substituting:

0.36 = k / (6)^2

k = 36*0.36 = 12.96 s the equation is F = 12.96 / d^2.

When d = 4.2 :

F = 12.96 / 4.2^2

F = 0.73 Newtons to 2 dp.