6. Three equal uniform rods, each of mass \(m\) and length \(2 a\), form the sides of a rigid equilateral triangular frame \(A B C\). The frame is free to rotate in a vertical plane about a fixed smooth horizontal axis \(L\) which passes through \(A\) and is perpendicular to the plane of the frame.

1. Show that the moment of inertia of the frame about \(L\) is \(6 m a ^ { 2 }\). The frame is held with \(A B\) horizontal and \(C\) below \(A B\), and released from rest. Given that the centre of mass of the frame is two thirds of the way along a median from a vertex,
2. find the magnitude of the force exerted by the axis on the frame at \(A\) at the instant when the frame is released.