Hi, I've drawn a diagram and derived that
0.2 * R = sin alpha * X + 0.5 cos alpha * W. where R is the normal reaction force where the drum meets the rod, W is the weight alpha is the angle the rod makes with the ground. I did this by taking moments at the point where the rod touches the ground. I also know that a vertical force destroys symmetry, I am just stuck at this point. Thanks for the help.
This is the question:
Two uniform rods AB and BC, each 1 metre and W newtons in weight, are connected at P by a smooth pin joint. The rods rest symmetrically in equilibrium in contact with a smooth cylindrical drum of radius 0.8 metes with its axis fixed and horizontal. Explain why the force from the pin on each rod is horizontal, and calculate the angle between the rods.