Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.

I really need help here.
A force of magnitude 7.50 N pushes three boxes with masses m_1 = 1.30 kg,m_2 = 3.20 kg, and m_3 = 4.90 kg .The mass is side by side.
1-Find the magnitude of the contact force between boxes 1 and 2, and
2-Find the magnitude of the contact force between boxes 2 and 3.

the position of the box like this:-
7.50N(push)-> |m1|m2|m3|