Problem 3.271

Find the interaction force of two coils with magnetic moments $p_{1 m}=4.0 \mathrm{~mA} \cdot \mathrm{m}^{2}$ and $p_{2 m}=6.0 \mathrm{~mA} \cdot \mathrm{m}^{2}$ and collinear axes if the separation between the coils is equal to $l=20 \mathrm{~cm}$ which exceeds considerably their linear dimensions